Question 177500
Solve for x in log form 
4^2X-4^X-42=0 
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Let 4^x = w
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Substitute to get:
w^2 - w - 42 = 0
(w-7)(w+6) = 0
w = 7 or w = -6
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Substitute to solve for "x":
4^x = 7 or 4^x = -6
No power of 4 can equal -6 so the only solution is that of 4^x=7
Takethe log of both sides to get:
xlog(4) = log(7)
x = log(7)/log(4)
x = 1.4036775...
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Cheers,
Stan H.