Answer
$y=-25x; -300$
Work Step by Step
We know direct variation has the equation y=kx. Thus, we plug in the points and solve for k:
$ y=kx \\\\ 125=-5k \\\\ k=-25$
We substitute k back in to get the equation: $y=-25x$
We now plug in x=12:
$y=(-25)(12)=-300$