A line passes through (9a, 7) and
(8, 5a). If its slope is 2, find a.

__Solution__
x1=9a, y1 = 7, x2 = 8, y2 = 5a

Slope(m) =

__y2 – y1__
x2 – x1

2 =

__5a – 7__
8 – 29a

__2__=

__5a – 7__[cross multiplying]

1
8 – 9a

2(8 – 9a) = 5a – 7

16 – 18a = 5a – 7

16 – 18a + 7 = 5a

16 + 7 = 5a+ 18a

23 = 23a

__23__=

__23a__

23 23

1 = a

__Hence a = 1__

__TRY THIS.................................__
A line passes through (2a, 5) and (4,
6a). If its slope is 8, find a.