bonjour
Réponse:
a. x/3 = x/4 - 6/5
X/3-X/4 = -6/5
4/12x-3/12x = -6/5
1/12x = -6/5
x = -6/5 *12
x = -6*12/5
x = - 72/5
b. 5x/8 - 3/10 = 7x / 40
5/8x -7/40x = 3/10
25/40x -7/40x=3/10
18/40 x =3/10
x=3/10*40/18
X = 120/180
x =12/18
x = 2/3
c. 2x/7+3/14 = x/7 - 1/14
2/7x -1/7x = -1/14 -3/14
1/7x=-4/14
1/7x = -2/7 x = -2/7 x 7
x =-14/7
x = -2
d. 2/5 x - 1/9 = 3/9 x + 4/5
2/5x -3/9x = 4/5 +1/9 18/45x -15/45 x = 36/45 +5/45
3/45x = 41/45 1/15x =41/45
x = 41/45 *15
x = 41/3
ps: quand il y a marqué .../.... c'est une fraction
