Question

If the slope of a line is -2/3 and contains the points (1,-5) and (-4a, 2) what is the value of a?

Answer 1

a = -11/4

Explanation:

Write an algebraic equation for the slope (using the definition of slope) and set the result = to the given -2/3:

rise 2-(-5) 2

m = ------------- = -------------- = - -------

run -4a - 1 3

Cross-multiply: 3(2+5) = -8a - 1.

Then 3(7) = -8a -1, or 22 = -8a. 22

Dividing both sides by -8, we get a = ---------

-8

or a = -11/4.