So you have to find the common base first which in this case is 3:
3^x=(3^2)^x+5
so now we can multiply the exponents on the right side of the equation:
3^x=3^2x+10
Now we can isolate the exponents to solve for x:
x=2x+10
subtract 2x from both sides
-x=10
divide the - on both sides
x= -10
so the answer is
x= -10
