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 + 5 = -147

8m = -147 - 5

8m = 152

8m = 152

8        8

m=19

Hence m=19.

TRY THIS…………………………..

NECTA 2004 QN 2a

Given that one of the roots of the equation 2x² + K(x+1) + 3 = 0 is 4, find K.