5.9 Multiplication of Monomials and Binomials

• Goals:

1. To multiply a monomial and a poly

2. To multiply 2 binomials (FOIL)

How to Multiply a Mono by a Poly:

• Distribute the mono by the poly

• i.e. Multiply ever term in the poly by the mono.

Multiply: 2x(5x + 3)(2x1)(5x1)

+(2x1)(3)

_____ PropertyDistributive

10x2 + 6x

Multiply: 3x2(-5x2 + 2x - 7)

4 3 215 6 21x x x

Multiplying 2 Binomials

• You can use the chart method

• You can FOIL

(Which ever method you choose remember to multiply every term together and collect like terms)

x

5x

2

x2 5x

2x

10

(x+5) (x+2)

X2 + 2x+ 5x +10 = x2 + 7x +10

(2x +3) (x-4)

x

32x

-4

2x2 3x

-8x -12

2x2 + 3x -8x -12 = 2x2- 5x -12

“F O I L” Multiplication

•F irst

•O uter

•I nner

•L ast

(x + 2) × (x + 3)

x2 + 3x

+ 2x

+ 6

x2 + 5x + 6

use FOIL to multiply

(2x + 1)(x + 3)

2x2 + 6x + x + 3

2x2 + 7x + 3

Use FOIL to multiply

(3x + 2)(x + 5)

3x2 + 15x

+ 2x

+ 10

3x2 + 17x + 10

Use FOIL to multiply(x + 3)(x - 5)

x2 - 5x + 3x - 15

x2 - 2x - 15

Use FOIL to multiply(5x - 1)(2x - 7)

10x2 – 35x - 2x +7

10x2 –37x + 7

Use FOIL to multiply(6x + 3)(x - 4)

6x2 - 24x + 3x - 126x2 - 21x - 12

Use FOIL to multiply

(2xy + 3x)(-2y - 5)

- 4xy2

- 10xy

- 6xy

- 15x

-4xy2 - 16xy – 15x

(2)(-2)(x)(y)(y)

AssignmentAssignmentPage 242 (16-54 even) Page 242 (16-54 even)

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