4x²/(2x-1) - 8/(2x-1)(2x+1) - (8x-7)/ 2x-1 =
4x²-8x+7/ 2x-1 - 8/(2x-1)(2x+1)=
(4x²-8x+7) (2x+1) / (2x-1)(2x+1) - 8/ (2x-1)(2x+1)
8x³+ 4x²-16x²-8x+14x+7-8/ (2x-1)(2x+1)
8x³-12x²+6x-1/ (2x-1) (2x+1) = (2x-1)(2x-1)²/(2x-1)(2x+1)= (2x-1)²/(2x+1)
8x³-4x²-8x²+4x+2x-1 = 4x²(2x-1)- 4x(2x-1) +1(2x-1)= (2x-1) (4x²-4x+1)=
=(2x-1) (2x-1)²
X∈ R\ {-1/2 ; 1/2}
