Question 1069399
First off, you have to take the logarithm of both sides:
12^(x-2)=20
log 12^(x-2)=log 20
(x-2)log 12=log 20
x-2=log 20/log 12
x=(log 20/log 12)+2=3.20557135368 ☺☺☺☺