Question

How do you factor the expression `y^2 +6y - 16`?

Answer 1

`y^2+6y-16 = (y+8)(y-2)`

Explanation:

Note that in general:

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

So we want to find a pair of factors `a` and `b` of `16` which differ by `6`.

The pair `8, 2` works in that `8-2=6` and `8*2 = 16`.

Hence:

`y^2+6y-16 = (y+8)(y-2)`