1)5^5x+1,5=25 2)6^6x-9=219 3)2^8-13x=1//32 4)7^1,2x+0,6=1//343 5)10^21-6x=0,001

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.