3 5x 81 x 1 July 8, 2019 16 32 64 128 3 5x 2 81 x 1 3 x 9 81 5x 1 81 3 x =( 1 3 5x 6 91 5x − 3 81 − x 14 3 x − 5 = 81 ( 1 3 ) x 81 x ≤ 5 5 3x+1 8=134 3