2*3^x=7*5^x
2*3^x=7*5^x rearrange as
(2/7) = (5^x / 3^x)
(2/7) = (5/3)^x take the log of both sides
log(2/7) = log(5/3)^x and we can write
log(2/7) = x log(5/3) divide both sides by log(5/3)
log(2 / 7) / log (5/3) = x ≈ -2.45
