College Algebra CLEP Prep Practice Exam

What is the slope of a line perpendicular to the line described by y = 5x - 30?

1. 5

2. 30

3. -5

4. -30

The correct answer is: -5

A) This is the slope of the original line, but not the line perpendicular to it. B) This is the y-intercept of the original line, but not relevant to finding the slope of a perpendicular line. D) This is the negative y-intercept of the original line, but not relevant to finding the slope of a perpendicular line. The slope of a perpendicular line would have to be the negative reciprocal of the original line's slope, which in this case is -5. This means that if you were to graph these two lines on the same coordinate plane, they would intersect at a 90 degree angle. Therefore, C is the correct answer.