Question

Factor  y2 – 400 thank you

Answer 1

We want to factor

`y^2-400`

This is difference of two squares, so we have

`y^2-20^2`

factoring, we have

`\begin{gathered} y(y)-20(20) \\ paring\text{ items outside the bracket we have } \\ (y-20) \\ paring\text{ items in the bracket, we have } \\ (y+20) \\ =(y-20)(y+20) \end{gathered}`

Hence the answer is

`(y-20)(y+20)`