Câu 2
a) (-105) + x = -217
x = -217 + 105
x = -112
b) x - 67 = -23
x = -23 + 67
x = 44
c) 4(3 - x) = 28
3 - x = 28 : 4
3 - x = 7
x = 3 - 7
x = -4
d) 5[x + (-81)] = 400
x - 81 = 400 : 5
x - 81 = 80
x = 80 + 81
x = 161
e) 140 : (x + 108) = 7
x + 108 = 140 : 7
x + 108 = 20
x = 20 - 108
x = -88
f) -27 + (-x) = -104
-27 - x = -104
x = -27 - (-104)
x = 77