SLOPE OR GRADIENT-1

A line passes through (3a, 27) and (8,5a). If its slope is 4, find a.

Solution

x1=3a, y1 = 27, x2 = 8, y2 = 5a

Slope(m) =    y2 – y1

                     x2 – x1

               4 =  5a – 27

                      8 – 3a

               4 =    5a – 27     [cross multiplying]

               1       8 – 3a

4(8 – 3a) = 5a – 27

32 – 12a = 5a – 27

32 – 12a + 27 = 5a

32 + 27 = 12a+ 8a

60 = 20a

60 = 20a

20    20

3 = a

Hence a = 3

TRY THIS.....................................

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