There are total 216 outcomes if we could calculate it manually, It is better to use online probability calculators like these:
It is better to use such online calculators so that we could save time also along with having the answer of the question. Technology has changed quite a lot over the past years that it is not difficult to get help from such resources on web. But with its facilities we cannot totally depend upon such tools, better approach is to solve such equations by hand and learning the concept of their calculations. But if we are to solve such questions for quiz or general Q&A then best thing is to use online tools.
It is not so difficult to solve this kind of questions. You just have to follow basic steps
1) Solve for x over the real numbers:
2^(2 x) + 2^(2 x + 1) = 3/8
2) Simplify and substitute y = 2^(2 x).
2^(2 x) + 2^(2 x + 1) = 3×2^(2 x) = 3 y:
3 y = 3/8
3) Divide both sides by 3:
y = 1/8
4) Substitute back for y = 2^(2 x):
2^(2 x) = 1/8
5) Take the logarithm base 2 of both sides:
2 x = -3
6) Divide both sides by 2:
x = -3/2
Now this is the manual calculation which requires some time to solve. If you don't have the concepts and yet want to solve such equations quickly then use online Quadratic Calculator.