3 5 x 1 25 9 July 8, 2019 16 32 64 128 3 5 x 1 25 9 exponential equation 3 x 1 )+ 25 5 9 x 15 3 x 9 y 5 x y 1 25 xy 3 x 1 )+ 25 chia hết cho 5 9 x 15 3 x-5=x+3
