50%x=70
x+120%x=88
82%x-40%x=42.
(1)50%x=70,
0.5x=70,
0.5x÷0.5=70÷0.5,
x=140,
(2)x+120%x=88,
x+1.2x=88,
2.2x=88,
2.2x÷2.2=88÷2.2,
x=40,
(3)82%x-40%x=42,
0.82x-0.4x=42,
0.42x=42,
0.42x÷0.42=42÷0.42,
x=100.
50%x=70
x+120%x=88
82%x-40%x=42.
(1)50%x=70,
0.5x=70,
0.5x÷0.5=70÷0.5,
x=140,
(2)x+120%x=88,
x+1.2x=88,
2.2x=88,
2.2x÷2.2=88÷2.2,
x=40,
(3)82%x-40%x=42,
0.82x-0.4x=42,
0.42x=42,
0.42x÷0.42=42÷0.42,
x=100.