Monoxdifly
MHB
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If $$4^x+4^{-x}=8$$, then $$8^x+8^{-x}=?$$
A. 14
B. 15
C. 16
D. 17
E. 18
What should I do? I tried substituting $$y = 4^x$$ but it didn't help since the quadratic equation formed didn't have real roots.
A. 14
B. 15
C. 16
D. 17
E. 18
What should I do? I tried substituting $$y = 4^x$$ but it didn't help since the quadratic equation formed didn't have real roots.