Question

Line p has a slope of -3. Line t is perpendicular to line p and passes through the point (9,2). What is the equation for line t?

Answer 1

y = (1/3)x - 1

Explanation:

The product of the slopes of perpendicular lines is -1. That makes the slopes of perpendicular lines negative reciprocals. Since line p has slope -3, the slope of line t is 1/3. Also, line t passes through point (9, 2).

y = mx + b

m = slope

y = (1/3)x + b

Now we replace x and y with the x- and y-coordinates of the given point, respectively, and we solve for b.

2 = (1/3)(9) + b

2 = 3 + b

b = -1

Now we replace b with -1.

y = (1/3)x - 1