Question

How do you multiply `(7+sqrt(5b))(7–sqrt(5b))`?

Answer 1

`= color(blue)(49 - 5b`

Explanation:

This is of the form :
`color(blue)((a+b)(a-b) = a^2 - b^2`
So ,
`(7+sqrt(5b))(7–sqrt(5b)) = 7^2 - sqrt((5b))^2`

`= color(blue)(49 - 5b`