Bonjour,
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
<=> x=-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
