1: (158-x):7=20
2: 231-(x-6)=1339 :13
3: 7.5(2x-3)=45
4: 156-(x+61)=82
5: 6.(5x+35)=330
6: 936-(4x -24)=72
7: 5.(3x+34)=515
8: (231-x) :8=25
9. : (7x-28).13=0
10: (2x-39).7+3=80
Giải hết ra nhé.
Đáp án:
1) (158-x):7=20
x=18
2) 231-(x-6)=1339 :13
x=134
3) 7.5(2x-3)=45
x=15/7
4)156-(x+61)=82
x=13
5) 6.(5x+35)=330
x=4
6) 936-(4x -24)=72
x=222
7)5.(3x+34)=515
x=23
8) (231-x) :8=25
x=31
9) (7x-28).13=0
x=4
10) (2x-39).7+3=80
x=25
Giải thích các bước giải:
1) (158-x):7=20
158-x=20.7
158-x=140
x=158-140
x=18
2) 231-(x-6)=1339 :13
231-(x-6)=103
x-6=231-103
x-6=128
x=128+6
x=134
3) 7.5(2x-3)=45
35(2x-3)=45
2x-3=45:35
2x-3=9/7
2x=9/7+3
2x=30/7
x=30/7:2
x=15/7
4)156-(x+61)=82
x+61=156-82
x+61=74
x=74-61
x=13
5) 6.(5x+35)=330
5x+35=330:6
5x+35=55
5x=55-35
5x=20
x=20:5
x=4
6) 936-(4x -24)=72
4x -24=936-72
4x-24=864
4x=864+24
4x=888
x=888:4
x=222
7)5.(3x+34)=515
3x+34=515:5
3x+34=103
3x=103-34
3x=69
x=69:3
x=23
8) (231-x) :8=25
231-x=25.8
231-x=200
x=231-200
x=31
9) (7x-28).13=0
7x-28=0
7x=0+28
7x=28
x=28:7
x=4
10) (2x-39).7+3=80
(2x-39).7=80-3
(2x-39).7=77
(2x-39)=77:7
(2x-39)=11
2x=11+39
2x=50
x=50:2
x=25