12-3x+1=6-2x+6
-3x+2x=6+6-12-1
-1x=-1
x=-1÷-1
x=1
3(4-1)+1=2(3-1)+6
3×3+1=2×2+6
10=10
2) 5-3x-7+2x=-3-2x
-3x+2x+2x=-3-5+7
x=-1
(5-3×(-1))-(7-2×(-1))=-3-2×(-1)
8-9=-1
-1=-1
3) 2x-19=8-x
2x+x=8+19
3x=27
x=27÷3
x=9
2×9-19=8-9
18-19=-1
4) 11-5x=31-10x
-5x+10x=31-11
5x=20
x=20÷5
x=4
11-5×4=31-10×4
11-20=31-40
-9=-9
12-3x+1=6-2x+6
-3x+2x=6+6-12-1
-1x=-1
x=-1÷-1
x=1
3(4-1)+1=2(3-1)+6
3×3+1=2×2+6
10=10
2) 5-3x-7+2x=-3-2x
-3x+2x+2x=-3-5+7
x=-1
(5-3×(-1))-(7-2×(-1))=-3-2×(-1)
8-9=-1
-1=-1
3) 2x-19=8-x
2x+x=8+19
3x=27
x=27÷3
x=9
2×9-19=8-9
18-19=-1
-1=-1
4) 11-5x=31-10x
-5x+10x=31-11
5x=20
x=20÷5
x=4
11-5×4=31-10×4
11-20=31-40
-9=-9