5x²-25x^5
= 5x²(1-5x^3)
(4x-2)(x+1)-(2x-1)(x+3)
=2(2x-1)(x+1)-(2x-1)(x+3)
=(2x-1)[2(x+1)-(x+3)]
=(2x-1)(2x+2-x-3)
=(2x-1)(x-1)
3(1-2x)+(x-1)(2x-1)
= 3(1-2x)-(x-1)(1-2x)
= (1-2x)[3-(x-1)]
= (1-2x)(3-x+1)
= (1-2x)(4-x)
4x²+4x+1
= (2x + 1)²
car identité remarquable
9x²-(3x-1)(x+1)-6x+1
= 9x²-6x+1-(3x-1)(x+1)
= (3x-1)² - (3x-1)(x+1)
= (3x-1)[(3x-1)-(x+1)]
= (3x-1)(3x-1-x-1)
= (3x-1)(2x-2)
4x-1/x+3
domaine : ]-oo ; -3[ U ]-3;+oo[
5x+1/4x²
domaine : IR*
3x-2/x²+1
domaine : IR
