Question

factor.
$y^2 - 12y + 20$

Explanation:

Step1: Find pair summing to -12, product 20

We need two numbers that add to $-12$ and multiply to $20$: $-10$ and $-2$.

Step2: Split middle term and factor

Rewrite the quadratic as $y^2 -10y -2y +20$, then factor by grouping:

$$\begin{align} y^2 -10y -2y +20 &= y(y-10) -2(y-10) \\ &= (y-10)(y-2) \end{align}$$

Answer:

$(y-10)(y-2)$