Hey guys... I am just finishing up my unit, and I had a question that I am stuck on..

Here it is:

Solve each of the following exponential equations:

b) 4(2^x) + 31 (2^x) - 8 = 0

So, I figure that I can replace (2^x) with just x, and then I would solve it like a complex trinomial.. However, it would then be 4x+31x -8, and I need it to be 4x^2 in order to do that. How am I supposed to solve this?

THanks