Objective 122 Square a binomial

©2002 by R. Villar All Rights Reserved

Square a binomial

We can use the FOIL method to square binomials… Example:

Multiply (5x – 6y) 2

This can be written as

(5x – 6y)(5x – 6y)

Now, use the FOIL method...

First

25x 2

Outer Inner Last

– 30xy – 30xy + 36y 2

Notice that the inner and outer are the same...

This will always happen when squaring a binomial.

25x 2 – 60xy + 36y 2

Let’s look at the parts of this product...

Square a binomial

We can use the FOIL method to square binomials… Example:

Multiply (5x – 6y) 2

square of the first term square of the second term 25x 2 – 60xy + 36y 2 This is the product of the terms, doubled

Example:

Multiply (4x – 3y) 2

square of the first term square of the second term 16x 2 – 24xy + 9y 2 Double the product of the terms

        

Example:

Multiply   4

x

2  1 2   2

square of the first term square of the second term

16

x

4

– 4

x

2  1 4

Double the product of the terms

  •    2   

2

4

x

2 1   •    1 2

1

     1

What is ?

2   2    1 2   •    1 2     2

x

2

Double this...