Represent as .4^x*4^(-1)=2^x+8
This is a question from the paper 1 of the last year's IB Math (HL) exam that my teacher gave out today.
Q: Solve the equation 4^(x-1)=2^x+8.
4^(x-1)=2^x+8
4^x*4^(-1)=2^x+8
4^(-1)=(1/2)^x+8/4^x
4^(-1)=1/2^x+8/4^x
Then I am stuck here.
I do know that the answer is 3 but I need to know the steps and working that lead to the answer in order to obtain full marks on the exam. Some help will be really appreciated!