Step-by-step 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 <em>a</em>, the slope of the other line should be <em>-1/a</em>.
Here we have -5 and 0.2, and indeed -1/-5 = 0.2, so they are perpendicular.
