What is the y-intercept of the line that is perpendicular to y = − 3x − 5 and passes through the point (−3, 7)?

Question

A) 23

B) 1/3

C) 8

D) 10

Answer 1

Perpendicular line has negative reciprocal slope

Since y=-3x - 5 then m= -3/1

So the slope of perpendicular line is m= 1/3

the equation. Y= 1/3 x + b

since the line passes through the point (-3,7)

this means when x = -3 then y= 7

7= -3 × 1/3 + b. Solve for b

7= -1 + b

b = 8

c: 8

Answer 2

Perpendicular lines have opposite, reciprocal slopes. We'll input the given point to find b.

7 = (1/3)(-3) + b

7 = -1 + b

b = 8

C