Question

How do you factor `4-49z^2`?

Answer 1

`(2+7z)(2-7z)`

Explanation:

The expression if the difference of two squares

`(a+b)(a-b)=a^2-ab+ab-b^2=a^2-b^2`

In this case

`a=2`, `a^2=4`

`b=7z`, `b^2=49z^2`