Bonsoir svp aidez moi pour les exercices 33 et 35

33
a
(5x+1)(8-x) = 0
⇔ 5x+1 = 0 ou 8-x = 0
⇔ 5x = -1 ou x = 8
⇔ x = -1/5 ou x = 8

b
(3x-1)+(7-x) = 0
⇔ 3x-1 +7-x= 0
⇔ 2x+6 = 0
⇔2x = -6
⇔ x = -6/2 = -3

c
(8+3x)-(x+3) = 0
⇔ 8+3x-x-3= 0
⇔ 2x+5 = 0
⇔ 2x = -5
⇔ x = -5/2

d)
(3-10x)(x+23) = 0
⇔ 3-10x = 0 ou x+23 = 0
⇔ 10x = 3 ou x = -23
⇔ x = 3/10 ou x = -23

e)
6(y+3)-2(y-1) = 0
6y+18-2y+2 = 0
4y +20 = 0
4y = -20
y = -20/4
y = -5

ex 35

x                       x
10x                  8x
10x-2              8x+7

10x-2 = 8x+7
10x-8x = 7+2
2x = 9
x = 9/2
x = 4,5