How do you solve 8^y = 4^(2x+3)8y=42x+3 and log2y=log2x+4log2y=log2x+4?

1 Answer

The first equation becomes

8^y=4^(2x+3)=>(2^3)^y=2^(2*(2x+3))=>3*y=4x+68y=42x+3(23)y=22(2x+3)3y=4x+6

The second equation becomes

log2y=log2x+4=>log((2y)/(2x))=4=>log(y/x)=4=> y/x=10^4=>y=10^4*xlog2y=log2x+4log(2y2x)=4log(yx)=4yx=104y=104x

Now the system of equations become

3y=4x+63y=4x+6
y=10^4*xy=104x

which has solutions

x = 3/14998x=314998, y = 15000/7499y=150007499