Answer
$y=-3$
Work Step by Step
$8y+7y=-45\rightarrow$ combine like terms
$15y=-45\rightarrow$ divide both sides by 15
$15y\div15=-45\div15\rightarrow$ simplify
$y=-3$
Check the soution by plugging in the value for y and determine whether the resulting equation is true.
$8(-3)+7(-3)=-45\rightarrow$ simplify
$-24+(-21)=-45\rightarrow$ simplify
$-45=-45$
This is true so the solution is correct.