a ) = -3 . ( x + 4 ) = 23-128
<=> 3 . ( x + 4 ) = -105
<=> x + 4 = -35
=> x = -39
b) <=> [(4x+28) ×3+55] = 175
<=> (4x+28) ×3 = 120
<=> 4x+28 = 40
<=> 4x = 12
=> x=12
c) (12x-4 ³)-8 ³ = 4 ×8^4
<=> (12x-4 ³) = 4 ×8^4 : 8^3
<=> 12x - 64 = 4 . 8
<=> 12x = 32 + 64
<=> 12x = 96
=> x = 8
=> x =