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Solve the equation `15.2^(x+1)+15.2^(2-x)=135` |
Answer» This equation rewrite in the form `30.2^x)+60/(2^(x))=135` Let `t=2^(x)` Then `30t^(2)-135t+60=0` `implies6t^(2)-27t+12=0` `implies6t^(2)-24t-3t+12=0` `implies(t-4)(6t-3)=0` Then `t_(1)=4` and `t_(2)=1/2` Thus, given equation is equivalen to `2^(x)=4` and `2^(x)=1/2` Then `x_(1)=2` and `x_(2)=-1` Hence roots of the original equation are `x_(1)=2` and `x_(2)=-1`. |
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