SOLUTION: Solve the following exponential equation: 9^(x+1)-3^(x+3)-3^x+3=0. Show your calculations.

Algebra ->  Exponents -> SOLUTION: Solve the following exponential equation: 9^(x+1)-3^(x+3)-3^x+3=0. Show your calculations.      Log On


   

Question 898996: Solve the following exponential equation: 9^(x+1)-3^(x+3)-3^x+3=0. Show your calculations.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
9%5E%28x%2B1%29-3%5E%28x%2B3%29-3%5Ex%2B3=0
%283%5E2%29%5E%28x%2B1%29-3%5E%28x%2B3%29-3%5Ex%2B3=0
3%5E%282%2A%28x%2B1%29%29-3%5E%28x%2B3%29-3%5Ex%2B3=0
3%5E%282x%2B2%29-3%5E%28x%2B3%29-3%5Ex%2B3=0
9%2A3%5E%282x%29-27%2A3%5E%28x%29-3%5Ex%2B3=0
9%2A3%5E%282x%29-28%2A3%5E%28x%29%2B3=0
Substitute u=3%5Ex
9u%5E2-28u%2B3=0
%28u-3%29%289u-1%29=0
Two solutions:
u-3=0
u=3
3%5Ex=3
x=1
and
9u-1=0
9u=1
u=1%2F9
3%5Ex=1%2F9
x=-2