Bonjour pouvez vous m’aidez à développer ces calcul svp a_(-X-5)(5-3X) b_ 2(X-3)-(4-X)+7 et à résoudre c’est calcul: a_7(X+3)-5=2-X b_4+3X=-(X+3)-5 Merci.

Bonjour,

a) (-x-5)(5-3x) = -5x+3x²-25+15x = 3x²+10x-25

b) 2(x-3)-(4-x)+7 = 2x-6-4+x+7 = 3x-3

c) 7(x+3)-5 = 2-x

<=> 7x+21-5 = 2-x

<=> 7x+17 = 2-x

<=>7x+x = 2-17

<=> 8x = -15

<=> x = -15/8

d) 4+3x = -(x+3)-5

<=> 4+3x = -x-3-5

<=> 4+3x = -x-8

<=> 3x+x = -8-4

<=> 4x = -12

<=> x = -12/4 = -3