The quadratic equation is x= -b ± b^2 - 4ac / 2a
So, when looking at a problem like these you have 4 options to chose from.
b) completing the square
c) solving using the quadratic equation
d) graphing (graphing calculator etc...)
12x^2 + 10x = 0
12x^2 + 10x + 25 - 25 = 0
If you want me to go on, I could. It might help for you to try the question from that point on, post your progress and I can help you from there.