Bonsoir
Factorisons
a) 4x²-4x+1
= (2x+1)²
b) 9x²+12x+4
= (3x+2)²
c) (2x+1)²-x²
= [(2x+1) + x][(2x+1) - x]
= (2x+1+x)(2x+1-x)
= (3x+1)(x+1)
d) = (x+3)²-(2x-3)²
= [(x+3)+(2x-3)][(x+3)-(2x-3)]
= (x + 3 + 2x - 3)(x + 3 - 2x + 3)
= (3x)(x+6)
e) 9x²-16
= (3x)² - 4²
= (3x + 2)(3x - 2)
f) (2x+1)² - (3x+1)(2x+1)
= (2x + 1)(2x + 1) - (3x + 1)(2x + 1)
= (2x + 1)[(2x + 1) - (3x + 1)]
= (2x + 1)(2x + 1 - 3x + 1)
= (2x + 1)(-x + 2)
Pour l'autre
1/4x² -1/3x +1/9
= (1/2x - 1/3)²