Je ne comprends rien aux polynômes à factoriser : 5x2-25x5; (4x-2)(x+1)-(2x-1)(x+3); 3(1-2x)+(x-1)(2x-1); 4x2+4x+1; 9x2-(3x-1)(x+1)-6x+1 Et donner la définition

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