6.5 Mult polynomials comp.notebook
January 10, 2017
6.5 Multiplying Polynomials
Multiplying by a Monomial
Ex. 1 Simplify (a) (4y3)(7y5)
(b)(3mn 2)(9m7n)
Ex. 2 Simplify (a) 4(3x 2 + 4x ­ 8)
(b) 3x 2 (2x+1)
Ex. 3 Simplify 5x(2x 3 +1) + 2x 2 (7x2 ­ 5)
SLATES
Feb 16­7:35 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
We can use the distributive property to multiply two binomials.
Ex. 3 Simplify (2x+1)(x­5)
Ex. 4 Find the product of (3x­4)(2x+3)
SLATES
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
TRY1 (6x ­ 7)(3x + 5)
TRY2 (4x + 3)(7x ­ 5)
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
FOIL
FOIL – First Outer Inner Last
FOIL is a very common method to multiply two binomials.
EX.5 Find the product of (3x ­ 5)(2x ­ 7)
EX.6 Using FOIL, find the product of (3x + 4)(7x + 5)
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
Use FOIL to find the product of TRY1 (3x ­ 4)(2x + 5)
TRY2 (3x + 4)(2x + 5)
TRY3 (3x ­ 4)(2x ­ 5)
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
Multiplying a Trinomial and a Binomial
FOIL does NOT work so well when multiplying a trinomial and a binomial. Instead we use the vertical or horizontal method.
EX.5 Find the product of (3x2 + x ­ 6)(2x ­ 3)
SLATES
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
TRY1 Simplify (3a + 4)(5a2 + 2a ­ 3)
TRY2 Simplify (2x2 + 3x + 3)(x ­ 3)
Feb 16­7:48 PM
6.5 Mult polynomials comp.notebook
January 10, 2017
Applications
The width of a rectangular prism is 5 feet less than the height, and the length of the prism is 6 feet more than the height.
(a) Write a polynomial that represents the area of the base of the prism.
(b) Find the area of the base when the height is 7 feet.
Feb 16­7:35 PM