What is an equation in point-slope form for the line perpendicular to y = 6x – 8 that contains (–10, 7)?

Question

a	y – 10 = (x + 7)
b	y – 7 = 6(x + 10)
c	y – 7 = (x + 10)
d	x – 7 = 6(y + 10)

Answer 1

The equation y = 6x - 8 is in slope-intercept form, y = mx + b, where m is the slope, so the slope of that line is 6.

The slope of the line perpendicular to that line is the negative reciprocal of 6, -1/6

Point slope form is y - y1 = m(x - x1), where (x1,y1) is a point on the line.

We are given that (-10,7) is a point on the line, so (x1,y1) = (-10,7). And m = -1/6, so substituting:

y - 7 = -1/6(x--10) --> y-7 = -1/6(x+10) (c)