Question

If x = -1/2 is a solution of the quadratic equation 3x2+2kx-3=0 find the value of k

Answer 1

6+2k(-1/2)-3=0. 
6+1k-3=0
3+1k=0
-3
k=-3

Answer 2

Just substitute for x :)

3(-1/2)2+2k(-1/2)-3=0
-3 + (-1k) -3 = 0 
-6 + (-1k) = 0 
+6            +6
-1k = 6 
/-1     /-1                    k = -6  that's what i believe the answer is