Multiply both sides by 4 and let . We want to satisfy the following system of equations: and .
Replacing the , and the coefficient for , we have:
That is obviously true. So, let's solve the system of equations:
and . Solving for in the second equation, we can plug it into the first:
Simplifying, we get . We can now solve for by plugging it into the quadratic equation:
Take the cube root of both sides, and you have . Plug that in for , and that gives you . Then, .
(This is the general method for solving a cubic equation).