7.1 #5 Subtracting
Polynomials
When subtracting polynomials distribute the negative one to all the
terms in the second set of parenthesis. Then combine like terms
just like you did for addition.
Example #1
(4n2 + 5)- (-2n2 + 2n – 4) Distribute -1
4n2 + 5 + 2n2 – 2n + 4
Combine Like Terms
4n2 + 2n2 – 2n + 5 +4
6n2 – 2n + 9
Example #2
(4x2 – 3x + 5) – (3x2 – x – 8) Distribute -1
4x2 – 3x + 5 – 3x2 + x + 8
Combine Like Terms
4x2 – 3x2 – 3x + x + 5 + 8
x2 – 2x + 13
Try these on your own
You should have gotten
10. 5p2 + 2p
11. -3k2 – k + 11
7.1 #6 Solving Real-Life Problems
a. Write a polynomial that represents the
distance between the penny and paintbrush
after t seconds.
To find the distance between them, you
must subtract the polynomials.
(-16t2 – 40 t + 200) – (-16t2 + 100)
b. Interpret the coefficients of the
polynomial in part a.
-40t + 100
When t = 0 we have -40(0) + 100
When the items are first dropped they are 100 feet
apart.
As t is increased by 1, the value of -40t + 100 decreases
by 40. This means that the objects become 40 feet
closer to each other every second.
Complete this in your notebook
Homework
Complete 7.1 Practice A # 8 - 19