CPM Homework Help : CALC Problem 2-129

What is the relationship between the slopes of perpendicular lines? If you know the slope of one of the lines, how can you find the slope of a line perpendicular to it?

Hint:

Choose a number to represent the slope of line $A$ .
Divide $−1$ by your number.
Simplify.
That is the slope of line $B$ .
How do the slopes compare?

Answer:

The slopes of perpendicular lines are negative reciprocals.