Answer
B. $y=-5x$ ; 75
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 \\\\ 10=-2k \\\\ k=-5$
We substitute k back in to get the equation: $y=-5x$
We now plug in x=-15:
$y=(-5)(-15)=75$