GRADIENT OR SLOPE 2

A line passes through (2a, 7) and (8,5a). If its slope is 10, find a.

Solution

x1=2a, y1 = 7, x2 = 8, y2 = 5a

Slope(m) =    y2 – y1

                     x2 – x1

               10 =  5a – 7

                      8 – 2a

               10 =    5a – 7     [cross multiplying]

               1       8 – 2a

10(8 – 2a) = 5a – 7

80 – 20a = 5a – 7

80 – 8a + 7 = 5a

80 + 7 = 5a+ 8a

87 = 13a

87 = 13a

13    13

a= ⁸⁷/13

a= 6 ⁹/13

Hence a= 6 ⁹/13

TRY THIS………………….. 

A line passes through (3a, 9) and (3,5a). If its slope is 10, find a.