Bonjour
a) 3x+7= x-2 3x-x = -7-2 2x = -9 x= -9/2 x= -4.5
verif → 3(-4.5) +7 = -4.5 -2 → -6.5 = -6.5
b) 2+2y = -1 +3y 2y -3y = -1 -2 -y = -3 y= 3
verif → 2 + 2(3) = -1 +3(3) → 2+6 = -1 +9 → 8 = 8
c) 4-5a = 2a-1 -5a -2a = -1 -4 -7a = -5 a = 5/7
verif → 4-5(5/7) = 2(5/7)-1 → 4 - 25/7 = 10/7 -1 →( 28-25)/7 = (10-7)/7
→ 3/7 = 3/7
d) t-4 = 3t-10 t-3t = -10+4 -2t =-6 t= 3
verif → 3-4 = 9-10 → -1 = -1