If the line passing through the points (a, 1) and (−14, 9) is parallel to the line passing through the points (−8, 8) and (a + 2, 1), what is the value of a?

Question

If the line passing through the points (a, 1) and (−14, 9)

 is parallel to the line passing through the points (−8, 8) and (a + 2, 1),

 what is the value of a?

Answer 1

(9-1)/(-14-a) = (8-1)/(-8 - (a+2))

8/(a+14) = 7/(a+10)

8(a+10) = 7(a+14)

8a + 80 = 7a + 98

a = 18

the slope is -1/4