Precalc
posted by Rebekah .
how do you find x in 7=log(x/10^12)

I will assume that = is a typo and should be just =
7 = log(x/10^12)
7 = logx  log 10^12
7 = logx  (12)
712= logx
5 = logx
x = 10^5 
the thing is its / instead of  so I thought that I multiply each side by 10^12 but im not sure

you cannot multiply by 10^12 because that is inside the log.
suppose you had 2 = √(x/4)
You can't multiply by 4, giving
8 = √x
because that would be trying to slide a value through the "walls" of the function calculation