The roots of the quadratic equation $3x^2+5x+k = 0$ are $\frac{-5\pm i\sqrt{131}}{6}$. What is $k$?
+122 solution from cphill:
We can solve for k in the discriminant thusly
5^2 - 4 (3)(k) = 131i^2 { i^2 = -1 and sqrt (-1) = i }
5^2 - 12k = -131
25 - 12k = -131
-12k = -131 - 25
-12k = -156
k = -156 / -12 = 13
