1) (5/6)^4x=(36/25)^-13
2)  5^x-9×5^x-3=580

( 5/6 ) ^ 4X = ( 36/25) ^ - 13 4X = ( - 2 * ( - 13 ))4X = 26 X = 6,5 --------------------------------5 ^X - 9 * 5 ^ ( X - 3 ) = 580 5 ^X * ( 1 - 9 * 5 ^(-3)) = 580 5 ^X * ( 1 - 9/125) = 580 5 ^X * 116/125 = 5805^X = 580 : 116/125 5^X = 625 5^X = 5^4X = 4 ----------------------------------