You can put this solution on YOUR website! Find all real solutions x to
4^x - 2^x = 56.
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2^(2x) - 2^x = 56
2^(2x) - 2^x - 56 = 0
Sub u for 2^x
u^2 - u - 56 = 0
(u-8)*(u+7) = 0
u = -7, u = 8
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2^x = 8 --> x = 3
That works.
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2^(-7) --> x = 1/128
that might work.
