If you want to solve for x, then the answer is x = 6*sqrt(2) where "sqrt" is shorthand for "square root"
Step-by-step explanation:
All logs below are base 4
log(5) - log(18) = log(20) - 2*log(x)
log(5) - log(18) = log(20) - log(x^2)
log(5/18) = log(20/x^2)
5/18 = 20/x^2 ... raise both sides as exponents (base = 4); logs cancel
5x^2 = 18*20 ... cross multiply
5x^2 = 360
x^2 = 360/5 ... divide both sides by 5
x^2 = 72
x = sqrt(72) ... see note below.
x = sqrt(36*2)
x = sqrt(36)*sqrt(2)
x = 6*sqrt(2)
note: we only consider the positive solution for x because x cannot be negative. We cannot input negative x values into log(x). The domain of log(x) is x > 0. So we don't consider "plus/minus" for the square root.