Sagot :
tu regroupe les X avec les X d'un coter je te fai la premier ex
9x-7x+19=27+7x-7x 2x +19=27 2x+19-19=27-19 2x=8 2x/2=8/2
x=4
1)9x+19=27+7x
9x+19-19=27+7x-19
9x-7x=27+7x-19-7x
9x-7x=27-19
2x=8
x=8/2
x=4
2)13+5x=2x+19
13+5x-13=2x+19-13
5x=2x+19-13
5x-2x=19-13
3x=6
x=6/3
2
3)7x-19=11-3x
7x-19+19=11-3x+19
7x=11-3x+19
7x+3x=11-3x+19+3x
7x+3x=11+19
10x=30
x=30/10
x=3
4)5x-12=7x-18
5x-12+12=7x-18+12
5x=7x-18+12
5x-7x=7x-18+12-7x
5x-7x=-18+12
-2x=-6
x=-6/-2
x=3
5)3x-5=-5x+27
3x-5+5=-5x+27+5
3x=-5x+27+5
3x+5x=-5x+27+5+5x
3x+5x=27+5
8x=32
x=32/8
x=4