
Douglas B. answered 06/11/20
HS and College Math: Clear and to the Point
First, find the slope of your line by solving for y:
y = 12 - (5/2)x. The slope is -5/2.
The line perpendicular has slope 2/5. This is because the product of the slopes of a line and its perpendicular line is -1.
Therefore, the perpendicular line has an equation of the form:
y = (2/5)x+b. We use the desired point on this line to find b.
-12 = y(8) = (16/5)+b. So, b = -12-16/5 = -76/5.
So, the equation of the perpendicular line is
y = (2/5)x - 76/5.