Question

Given the equation of a line: y = 3x - 7. Select the equation of the line PERPENDICULAR to this line

Options:
y = (1/3)x + 1/7
y = -3x + 7
y = (-1/3)x - 7
y = 3x + 2

Answer 1

The third option, y=(-1/3)x-7

Explanation:

To find a line perpendicular to an equation, you find the negative reciprocal of the slope. For instance, if you have an equation y=4x+5, the negative reciprocal is y=(-1/4)x+5. That is the equation to find a line perpendicular to this.

If you want to find a line parallel to the equation y=4x+5, all you have to do is come up with another equation that has the same slope. So, y=4x+8 would be a line parallel to the equation y=4x+5.