Question 83498
Start with the fact that perpendicular lines have slopes that are the negative reciprocal of each other.
So the slope of the line passing through the given points of (5, -6) and (-9, y) is going to be the negative reciprocal of {{{14/5}}} and this is {{{- 5/14}}}
Now you know what the slope is, you can apply the slope formula{{{m = (y[2]-y[1])/(x[2]-x[1])}}} using the given points and you know that the result is going to be equal to {{{-5/14}}}.
{{{(y[2]-y[1])/(x[2]-x[1]) = -5/14}}} Substitute the x- and y-coordinates of the given points.
{{{(y-(-6))/(-9-5) = -5/14}}} Simplify and solve for y.
{{{(y+6)/(-14) = -5/14}}} Multiply both sides by -14.
{{{y+6 = 5}}} Subtract 6 from both sides.
{{{y = -1}}}
Answer D) is the correct choice.