SOLUTION: Solve: {{{ 4^x-2^x-12=0 }}}

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Question 433500: Solve: +4%5Ex-2%5Ex-12=0+
Answer by belle3833(46) About Me  (Show Source):
You can put this solution on YOUR website!
+4%5Ex-2%5Ex-12=0+
=2%5E%282x%29-2%5Ex-12=0
ley y=2%5Ex
so we have:
y%5E2-y-12=0
=%28y-4%29%28y%2B3%29=0
y=4,y=-3
sincey=2%5Ex
we need to solve 2%5Ex=4 and 2%5Ex=-3

2%5Ex=-3 has no solutions so we look at 2%5Ex=4. here x=2