a) (2x-1)5 = 2x-1
=> (2x-1)5 - (2x-1) = 0
(2x-1).[(2x-1)4 -1]=0
=> 2x-1 =0 => 2x = 1=> x = 1/2
(2x-1)4 - 1= 0 => (2x-1)4 = 1 = 14 = (-1)4
=> 2x-1= 1 => 2x = 2 => x = 1
2x -1 = -1 => 2x = 0 => x = 0
KL:...
b) 25x.43 = 169
25x = (42)9:43
25x = 418:43
25x = 415 = (22)15 = 230
=> 5x = 30 => x = 6
c) 3x+1+4.3x = 7.36
3x.3+4.3x = 5013
3x.(3+4) = 5013
3x.7 = 5013
3x = 729 = 36
=> x = 6