QUADRATICS 1

Given that one of the roots of the equation 3x² + m(x+1) + 5 = 0 is 7, find m.

Solution

Substitute x=7, in the above equation.

3(7)² + m(7+1) + 5 = 0

(3x49) + (m x 8) + 5 = 0

147 + 8m + 5 = 0

8m + 152 = 0

8m = -152

8m = -152

8          8

m=^-152/8

Hence m=^-152/8

TRY THIS…………………………..

Given that one of the roots of the equation 3x² + m(x+1) + 3 = 0 is 8, find m.