Question

What is the slope of a line perpendicular to y = -7/4x?

Answer 1

A line is perpendiculat to another which has a slope of m if the perpendicular line has a slope of -1/m.
That means that if the product of slopes of two lines is -1, the two lines are perpendicular.

Here, y1=-7/4x, or m=-7/4
The perpendicular should have a slope of -1/m=-1/(-7/4)=4/7