What is the y-intercept of the line that passes through the point (-8,7) and is perpendicular to the line y=2x+5?

Answer 1

y-7 = (-1/2)(x+8) in point slope form

y-7 = -x/2 -4

y-7 = -x/2 -4 + 7

y = -x/2 +3

multiply by 2

2y = -x + 6

x +2y = 6

slope of a perpendicular line has a negative inverse slope. take 2, change its sign, flip it upside down to get -1/2.