GRADIENT 1

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.