Question

How do you factor `25z^2 - 36b^2`?

Answer 1

`=color(blue)((5z + 6b) (5z - 6b)`

Explanation:

`25 z^2 - 36b^2`

The expression can also be written as:
`(5 z) ^2 - (6b)^2`

This is of the form :
`color(blue)(a^2 - b ^2 = (a+b)(a-b)`

`(5 z) ^2 - (6b)^2 = color(blue)((5z + 6b) (5z - 6b)`

The factorised form of the expression is:
`color(blue)((5z + 6b) (5z - 6b)`