Question 48041
I got:
log 7^x/2 = log 5^1-x
(x/2)log7 = (1-x)log5 
Now you need to solve for "x", as follows:
x/(1-x)=(2)(log5/log7) =2(0.827...)=1.65
x=1.65-1.65x
2.65x=1.65
x=0.624...
Cheers,
Stan H.