1. Definition of a Polynomial

Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
1.
Definition of a Polynomial

What is a polynomial?
ο‚§
A polynomial 𝑃(π‘₯) is an algebraic expression of the form
Degree
𝑃(π‘₯) = π‘Žπ‘› π‘₯
𝑛
+ π‘Žπ‘›βˆ’1 π‘₯ π‘›βˆ’1 + π‘Žπ‘›βˆ’2 π‘₯ π‘›βˆ’2 + β‹― + π‘Ž3 π‘₯ 3 + π‘Ž2 π‘₯ 2 + π‘Ž1 π‘₯ + π‘Ž0
Leading term
Constant
Leading coefficient
where all powers of π‘₯ are integers greater than or equal to zero.
–
π‘Ž0 , π‘Ž1 , π‘Ž2 , … , π‘Žπ‘› are called coefficients, π‘Žπ‘› is called the leading coefficient.
–
π‘Ž0 is called the constant term.
–
π‘Žπ‘› π‘₯ 𝑛 is called the leading term.
–
The degree refers to the highest power of π‘₯
ο‚§
When π‘Žπ‘› = 1, the polynomial is called a monic polynomial.
ο‚§
𝑃(π‘₯) is a constant polynomial if π‘Ž1 = π‘Ž2 = … = π‘Žπ‘› = 0 and 𝑃(π‘₯) = π‘Ž0 (where π‘Ž0
is some constant).
ο‚§
If all the co-efficients are zero, i.e. π‘Ž0 = π‘Ž1 = π‘Ž2 = … = π‘Žπ‘› = 0 then the polynomial
𝑃(π‘₯) = 0 is called a zero polynomial or a polynomial equation of degree 0.
ο‚§
Real values of π‘₯ that satisfy the equation 𝑃(π‘₯) = 0 are called the real roots or
zeroes of the polynomial.
Note To Students:
When solving the roots or zeroes of a polynomial, this is also solving the
π‘₯ βˆ’intercepts of the polynomial. This will be useful when graphing the
polynomial in Lesson 4.
Copyright © MATRIX EDUCATION 2017
Page 8 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
Example 1
Consider the following polynomial.
𝑃(π‘₯) = 3π‘₯ 2 + 4π‘₯ – 7
Label the polynomial with the following terms.
(i)
Leading coefficient
(ii)
Constant term
(iii)
Leading term
[1]
[2]
[3]
What is the degree of the polynomial? [4]…………………………………………..…………
Is this a monic polynomial? Why or why not?
[5]
…………………………………………………………………………………………….………
Example 2
Identify the leading coefficient for each of the following polynomials and determine if it is monic
or non- monic.
(a)
𝑃(π‘₯) = π‘₯ + 1
……………………………………………………………………………………………………
……………………………………………………………………………………………………
(b)
𝑃(π‘₯) = 3 βˆ’ 6π‘₯ + 9π‘₯ 2 βˆ’ 12π‘₯ 3
……………………………………………………………………………………………………
……………………………………………………………………………………………………
(c)
𝑃(π‘₯) = π‘₯ 6 βˆ’ π‘₯ 9 + 1
……………………………………………………………………………………………………
……………………………………………………………………………………………………
(d)
𝑃(π‘₯) = 5π‘₯ 2 βˆ’ 10π‘₯ + 15
……………………………………………………………………………………………………
……………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 9 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
(a)
Consider the polynomial 𝑃(π‘₯) = 2π‘₯ 4 + 4π‘₯ 3 βˆ’ 2π‘₯ 2 + 5π‘₯ βˆ’ 6.
Complete the following:
(b)
LESSON 1: POLYNOMIALS 1
[6]
(iv)
The degree of the polynomial is …………………..
(v)
The leading term is ……………………………..…..
(vi)
The leading coefficient is …………………………..
(vii)
The constant term is …………..……………………
(viii)
The coefficient of π‘₯ 2 is ……………………………..
(ix)
The polynomial has ………………..……….. terms.
Write down a monic polynomial of degree 3 with a constant term of 5.
[7]
NOTE TO STUDENTS
Monic means that the leading coefficient is 1.
…………………………………………………………………………………………………………
(c)
5
π‘₯
Explain why 𝑃(π‘₯) = 5π‘₯ 2 βˆ’ 3π‘₯ 5 + 4π‘₯ + βˆ’ 1 is not a polynomial.
[8]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(d)
State the degree, leading coefficient and constant term of 𝑃(π‘₯) = (π‘₯ 2 + 2)(π‘₯ 4 βˆ’ 3) βˆ’ π‘₯ 6 .
[9]
NOTE TO STUDENTS
You must expand first and remember to always write your polynomials with the highest
power at the front down to the lowest power at the end.
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 10 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
State whether or not the following algebraic expressions is a polynomial. If it is a polynomial, state
the degree. If it is not a polynomial, give a reason.
1
(a)
5π‘₯ 3 βˆ’ 7π‘₯ 2 βˆ’ 2
[10]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(b)
π‘₯ 2 +3
4
[11]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(c)
2
3π‘₯ 2 +10
[12]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(d)
√2π‘₯ + 3
[13]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 11 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
Write the following polynomials in the form 𝑃(π‘₯) = π‘Žπ‘› π‘₯ 𝑛 + π‘Žπ‘›βˆ’1 π‘₯ π‘›βˆ’1 + π‘Žπ‘›βˆ’2 π‘₯ π‘›βˆ’2 + … . . + π‘Ž1 π‘₯ + π‘Ž0 and
hence state:
(i)
The degree.
(ii)
The constant term.
(iii)
The coefficient of the π‘₯ 3 term.
(iv)
The leading term.
(v)
Whether or not the polynomial is monic.
(a)
𝑃(π‘₯) = π‘₯ 2 + 2π‘₯ 3 + 8 βˆ’ 7π‘₯
[14]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(b)
𝑃(π‘₯) = (2π‘₯ + 3)(π‘₯ 2 βˆ’ 4)
[15]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(c)
𝑃(π‘₯) = π‘₯ 3 (8π‘₯ + 1) + 7π‘₯ βˆ’ 11 βˆ’ (2π‘₯ 2 βˆ’ 1)(4π‘₯ 2 βˆ’ 3)
[16]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 12 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV

LESSON 1: POLYNOMIALS 1
The language of polynomials
ο‚§
The notation 𝑃(π‘₯) is the same as 𝑓(π‘₯) from the β€˜Functions and Relations’ topic from
last term. 𝑃(π‘₯) is a polynomial with π‘₯ as the variable of the polynomial. When
evaluating:
–
𝑷(𝟐), substitute the value of 2 in place of all 𝒙 values.
–
𝑷(𝒂), substitute the value of 𝒂 in place of all 𝒙 values.
–
𝑷(𝒂 + 𝟏), substitute the value of (𝒂 + 𝟏) in place of all 𝒙 values.
Example 1
Consider the polynomial 𝑃(π‘₯) = π‘₯ 3 + 2π‘₯ 2 βˆ’ 6π‘₯ + 1. Evaluate 𝑃(2).
Solution
To find the value of 𝑃(2), substitute π‘₯ = 2 into 𝑃(π‘₯).
𝑃(2) = (2)3 + 2(2)2 βˆ’ 6(2) + 1 = 5
Therefore 𝑃(2) = 5.
Example 2
Given 𝑃(π‘₯) = βˆ’3π‘₯ 3 + 2π‘₯ + 9, evaluate the following.
(a)
𝑃(βˆ’1). [17]
……………………………………………………………………………………
……………………………………………………………………………………
(b)
𝑃(π‘š). [18]
……………………………………………………………………………………
(c)
𝑃(π‘₯ βˆ’ 1). [19]
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 13 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
(a)
LESSON 1: POLYNOMIALS 1
Given 𝑃(π‘₯) = π‘₯ 3 βˆ’ 3π‘₯ 2 βˆ’ π‘₯ + 1, evaluate 𝑃(βˆ’2), 𝑃(1) and 𝑃(3).
[20]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(b)
π‘₯
3
Given 𝑃(π‘₯) = βˆ’π‘₯ 4 βˆ’ 2π‘₯ 3 + π‘₯ 2 βˆ’ 10, evaluate 𝑃(3π‘Ž) and 𝑃 ( ).
[21]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 14 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
2.
Operations with Polynomials

Addition and subtraction
ο‚§
The sum or difference of two polynomials is found by collecting β€œlike terms”.
(π‘Žπ‘› π‘₯ 𝑛 + π‘Žπ‘›βˆ’1 π‘₯ π‘›βˆ’1 + β‹― + π‘Ž2 π‘₯ 2 + π‘Ž1 π‘₯ + π‘Ž0 ) ± (𝑏𝑛 π‘₯ 𝑛 + π‘π‘›βˆ’1 π‘₯ π‘›βˆ’1 + β‹― + 𝑏2 π‘₯ 2 + 𝑏1 π‘₯ + 𝑏0 )
= (π‘Žπ‘› ± 𝑏𝑛 )π‘₯ 𝑛 + (π‘Žπ‘›βˆ’1 ± π‘π‘›βˆ’1 )π‘₯ π‘›βˆ’1 + β‹― + (π‘Ž2 ± 𝑏2 )π‘₯ 2 + (π‘Ž1 ± 𝑏1 )π‘₯ + (π‘Ž0 ± 𝑏0 )
ο‚§
To add or subtract polynomials:
(i) Find the matching degree 𝒏 terms and
(ii) Add or subtract their coefficients.
Example 1
Fully simplify the following polynomials.
(a)
𝑃(π‘₯) + 𝑄(π‘₯)
𝑃(π‘₯) βˆ’ 𝑄(π‘₯)
(b)
𝑃(π‘₯) = π‘₯ 3 βˆ’ 3π‘₯ 2 + 4π‘₯ βˆ’ 12
𝑃(π‘₯) = 5π‘₯ 4 βˆ’ 0π‘₯ 3 βˆ’ 9π‘₯ 2 + 10π‘₯ βˆ’ 3
𝑄(π‘₯) = 7π‘₯ 3 + 2π‘₯ 2 βˆ’ 3π‘₯ + 8
𝑄(π‘₯) = 2π‘₯ 4 + 2π‘₯ 3 βˆ’ 10π‘₯ 2 + 5π‘₯ βˆ’ 9
Example 2
Consider the polynomials 𝑃(π‘₯) = 3π‘₯ 3 βˆ’ π‘₯ + 4 and 𝑄(π‘₯) = π‘₯ 3 + 2π‘₯ 2 βˆ’ 5π‘₯ + 1.
What is the sum of the two polynomials?
[22]
Solution
𝑃(π‘₯) + 𝑄(π‘₯) = (3π‘₯ 3 βˆ’ π‘₯ + 4) + (π‘₯ 3 + 2π‘₯ 2 βˆ’ 5π‘₯ + 1)
= (3π‘₯ 3 + π‘₯ 3 ) + (2π‘₯ 2 ) + (βˆ’π‘₯ βˆ’ 5π‘₯) + (4 + 1)
=……………………………………………………………
Note To Students:
Remember to write the polynomial in β€˜Degree’ order when solving addition or
subtraction of polynomials. This includes adding a zero- coefficient for terms
that are not included.
e.g.
𝑃(π‘₯) = π‘₯ 2 βˆ’ 3π‘₯ 4 + 3π‘₯ βˆ’ 1
Hence, 𝑃(π‘₯) = βˆ’3π‘₯ 4 + 0π‘₯ 3 + π‘₯ 2 + 3π‘₯ βˆ’ 1
Copyright © MATRIX EDUCATION 2017
Page 15 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.
Y10 MATHS ADV
LESSON 1: POLYNOMIALS 1
Consider the polynomials 𝑃(π‘₯) = 2π‘₯ 3 βˆ’ 4π‘₯ 2 βˆ’ π‘₯ + 3 and 𝑄(π‘₯) = βˆ’π‘₯ 3 + π‘₯ 2 βˆ’ 3π‘₯ βˆ’ 5.
(a)
Given 𝐴(π‘₯) = 𝑃(π‘₯) βˆ’ 𝑄(π‘₯), find 𝐴(π‘₯) and hence evaluate 𝐴(3).
[23]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(b)
Given 𝐡(π‘₯) = 2[𝑃(π‘₯) + 𝑄(π‘₯)], find 𝐡(π‘₯) and hence evaluate 𝐡(βˆ’1).
[24]
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
Copyright © MATRIX EDUCATION 2017
Page 16 of 188
OUR STUDENTS COME FIRST.
All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form,
or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of Matrix Education.