Answer
$(y+5)(y-6)$
Work Step by Step
To factor a trinomial in the form $y^2+bx+c$, we must find two numbers whose product is $c$ and whose sum is $b$. We then insert these two numbers into the blanks of the factors $(y+\_)(y+\_)$.
In the case of $y^2-y-30$, we are looking for two numbers whose product is $-30$ and whose sum is $-1$. The numbers $5$ and $-6$ meet these criteria because $$5\times-6=-30\;\text{and}\;5+(-6)=-1$$When we insert these numbers into the blanks, we arrive at the factors $(y+5)(y-6)$.
