1) 5^(5x - 1,5) =5^2;
5x - 1,5 = 2;
5x = 3,5;
x = 0,7.
2)6^(6x - 9) = 216;
6^(6x - 9) = 6^3;
6x - 9 =3;
6x = 12;
x = 2.
3) 2^(8 - 13 x) = (1/2)^5;
2^(8 -13 x ) = 2^(-5);
8 - 13 x = -5;
- 13 x = - 13;
x =1.
4) 7^(1,2 x + 0,7) = 7^(-3);
1,2 x + 0,6 = -3;
1,2 x = - 3,6;
x = 3.
5) 10^(21 - 6x) = 10^(-3);
21 - 6x = -3;
- 6x = - 24;
x= 4.