Sagot :
Ex 2 (2x+3)(5-x) - (2x+3)^2
2xX5-2xXx+3X5-3Xx-2xX2x+2xX3
10x-2x^2+15-3x-4x^2+6x
13x-6x^2+15
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Bonjour
3)
M = (3x-4)²-(x-5)(3x-4)
développer
M = 6x²-5x-4
factoriser
M= (3x-4)(3x-4-x+5)
M =( 3x-4)(2x+1)
M = 0 si l'un des facteurs = 0
3x-4 = 0 si x = 4/3
2x+1 = 0 si x = -1/2
si x = -2
M = -10 * -3 = 30