Question

the slope of a line is -4 and its y-intercept is (0,4). what is the equation of the line that is perpendicular to the first line and passes through (-8,2)

Answer 1

general linear equation y=mx+c
m=gradient/slope c=y-intercept

we are given gradient=-4
y-intercept = 4
y=-4x + 4 <<this is the equation we can come up with.

perpendicular meaning we have to follow the rule
m1 x m2 = -1
m1=gradient of our known equation which we figured above (-4)
m2=gradient of our unknown equation which we want to find.

-4 x m2 = -1
m2 = -1/-4
m2 = 1/4

use the point (-8,2) and m=1/4 to substitute into the general linear equation to find ur c value then re-write the whole thing.