(2/3)^x+(2/3)^x-1=2,5

Question

(2/3)^x+(2/3)^x-1=2,5

Answer 1

(2/3)^x + (2/3)^(x-1) = 2,5
(2/3)^x + (2/3)^x * (2/3)^(-1) = 2,5
(2/3)^x + (3/2) * (2/3)^x = 5/2
5/2 * (2/3)^x = 5/2
(2/3)^x = 1
(2/3)^x = (2/3)^0
x = 0