Question

A line has a slope of -13. There is a second line that passes through points (-7,-5) and (6,-4) . Would these lines be parallel , perpendicular or neither ?

Answer 1

Answer: The lines are perpendicular

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Work Shown:

Use the slope formula to find the slope of the line through the two given points.

m = (y2 - y1)/(x2 - x1)

m = (-4 - (-5))/(6 - (-7))

m = (-4 + 5)/(6 + 7)

m = 1/13

The slope of the line through the two given points is 1/13.

This is not equal to -13, which was the slope of the first line, so the two lines are not parallel.

However, the two lines are perpendicular because multiplying the two slope values leads to -1

(slope1)*(slope2) = (-13)*(1/13) = -1

note: It might help to think of -13 as -13/1 to help multiply the fractions.