Question

Y=4-5x y=.2x -4.5 perpendicular? Why?

Answer 1

Explanation:

Just look at the slopes, i.e., the factor before the x. They should be reciprocal to have perpendicular lines.

Reciprocal means that if the slope of one line is a, the slope of the other line should be -1/a.

Here we have -5 and 0.2, and indeed -1/-5 = 0.2, so they are perpendicular.