1. (25/9)^x *(27/125)^(x-5)=5/3, ((5/3)²)^x *((3/5)³)^(x-5)=5/3
(5/3)^(2x) *(3/5)^(3x-15)=5/3, (5/3)^(2x)*((5/3)⁻¹)^(3x-15)=5/3
((5/3)^(2x))*((5/3)^(-3x+15))=5/3, ((5/3)^(2x-3x))*((5/3)¹⁵)=5/3
(5/3)^(-x)=(5/3):(5/3)¹⁵, (5/3)^(-x)=(5/3)⁻¹⁴
-x=-14, x=14
2. (5/6)^(x²-2x)=(5/6)^(6-x)
x²-2x=6-x, x²-x-6=0, x₁=3, x₂=-2
3. 2^(1-x)*2^(2x)=64⁻¹
2^(1-x+2x)=(2⁶)⁻¹
2^(1+x)=2⁻⁶
1+x=-6, x=-7