First find the gradient of the perpendicular line. You do this by taking the negative reciprocal of the gradient of the first line (y= 1/4x +3):
Perpendicular gradient = negative reciprocal of [tex]\frac{1}{4}[/tex] = -4
Next, you substitute the x and y values into the following equation and solve:
y = -4x +c
-2 = -4(-4) +c
-2 = 16 + c
-18 = c
Substitute c back into the equation above to get the final answer:
y = -4x -18
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Answer
y = -4x - 18
