a) développer puis réduire et ordonner E
E = (2x-3)² + (5-3x)(2x-3)e = 4x²-12x+9 +10x-15-6x²+9x
e = -2x²+7x-6
b) calculer E pour x = 1/2
e = -2(1/2)² +7(1/2) -6
e = -2(1/4) +7/2 -6
e = -2/4 +7/2-6
e = -1/2 +7/2 -12/2
e = -13/2+7/2
e = -6/2
e = -3 c) factoriser E
E = (2x-3)² + (5-3x)(2x-3)e =(2x-3)(2x-3+5-3x)
e =(2x-3)(-x+2)
d) résoudre (2x-3)(2-x) = 0
2x-3 = 0
2x =3
x = 3/2
2-x =0
-x =-2
x =2
solution 3/2 et 2
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a) développer puis réduire et ordonner E
E = (2x-3)² + (5-3x)(2x-3)
e = 4x²-12x+9 +10x-15-6x²+9x
e = -2x²+7x-6
b) calculer E pour x = 1/2
e = -2x²+7x-6
e = -2(1/2)² +7(1/2) -6
e = -2(1/4) +7/2 -6
e = -2/4 +7/2-6
e = -1/2 +7/2 -12/2
e = -13/2+7/2
e = -6/2
e = -3
c) factoriser E
E = (2x-3)² + (5-3x)(2x-3)
e =(2x-3)(2x-3+5-3x)
e =(2x-3)(-x+2)
d) résoudre (2x-3)(2-x) = 0
2x-3 = 0
2x =3
x = 3/2
2-x =0
-x =-2
x =2
solution 3/2 et 2
=4x²+9-12x + 10x-6x²-6
=4x²-6x²-12x+10x+9-6
=-2x²-2x+3