Réponse :
Explications étape par étape
Bonjour
Exercice 1)
3x + 1 = 2x - 1
3 * 2 + 1 = 2 * 2 - 1
6 + 1 = 4 - 1
7 = 3
[tex]7 \ne 3[/tex] donc 2 n’est pas solution
3(x + 1) - 3(2 - x) = x + 1
3(2 + 1) - 3(2 - 2) = 2 + 1
3 * 3 - 3 * 0 = 3
9 - 0 = 3
9 = 3
[tex]9 \ne 3[/tex] donc 2 n’est pas solution
(2x + 1)/(3x + 4) = 1/2
(2 * 2 + 1)/(3 * 2 + 4) = 1/2
(4 + 1)/(6 + 4) = 1/2
5/10 = 1/2
1/2 = 1/2 => 2 est solution
[tex]\sqrt{3 * 2^2 + 4} = 4[/tex]
[tex]\sqrt{3 * 4 + 4} = 4[/tex]
[tex]\sqrt{12 + 4} = 4[/tex]
[tex]\sqrt{16} = 4[/tex]
4 = 4 => 2 est solution
Exercice 2 :
Factoriser :
(3x + 2)(2 - 2x) + (3x + 2)(x + 4)
= (3x + 2)(2 - 2x + x + 4)
= (3x + 2)(-x + 6)
(x - 1)(2x - 2) + (2x - 2)(5 - 2x)
= (2x - 2)(x - 1 + 5 - 2x)
= 2(x - 1)(-x + 4)
(4 - 3x)(x + 5) - (4 - 3x)(x + 2)
= (4 - 3x)(x + 5 - x - 2)
= (4 - 3x)(3)
= 3(4 - 3x)
(2x + 5)(x + 2) - (2x + 5)
= (2x + 5)(x + 2 - 1)
= (2x + 5)(x + 1)
Developper :
3(x + 2) - 4(2 - 2x)
= 3x + 6 - 8 + 8x
= 11x - 2
(3 - x)(2x + 1) + 2(x + 2)
= 6x + 3 - 2x^2 - x + 2x + 4
= -2x^2 + 7x + 7
-(5 - 2x) + (x + 3)(2x + 1)
= -5 + 2x + 2x^2 + x + 6x + 3
= 2x^2 + 9x - 2
x(1 + x) - (x + 2)(3 - x)
= x + x^2 - (3x - x^2 + 6 - 2x)
= x^2 + x^2 + x - x - 6
= 2x^2 - 6
