Question 1082041
9^(-r) = 9^(1-2r)


this is true if and only if -r = 1 - 2r


add 2r to both sides of the equation to get 2r - r = 1 which becomes r = 1


9^(-r) becomes 9^-1 which becomes 1/9^1 which becomes 1/9


9^(1-2r) becomes 9^(1-2) which becomes 9^-1 which becomes 1/9


the solution of r = 1 is confirmed to be correct.