Question

How do you find the product `(6y-7)(6y+7)`?

Answer 1

`36y^2-49`

Explanation:

Each term in the second bracket is multiplied by each term in the first bracket. This can be achieved as follows.

`(color(red)(6y-7))(6y+7)`

`=color(red)(6y)(6y+7)color(red)(-7)(6y+7)`

`=(color(red)(6y)xx6y)+(color(red)(6y)xx7)+(color(red)(-7)xx6y)+(color(red)(-7)xx7)`

`=36y^2+42y-42y-49`

`=36y^2-49larrcolor(magenta)" difference of squares"`