Question

How do you factor the trinomial `y²-49`?

Answer 1

`(y+7)(y-7)`

Explanation:

This is a difference of squares—the `y^2` is `(y)^2` and `49` is `(7)^2`.

This is the rule for a difference of squares: `a^2-b^2=(a+b)(a-b)`

Thus, `y^2-49=(y+7)(y-7)`.