one variable
x+6=12
x=6
2x+y=5
-3x+6y=0
x=2
y=1
4x+6y+5z=70
4x+6y=60
3x=18
x=6
y=6
z=2
15+15=
30
4x-12=24
x=9
2b-5x=-19
-b=-3
x=5
4a+b+3v=31
4a+b=25
5a=30
a=6
b=1
v=2
400/10+17(42-5)=
669
2x-42=6x-38
x=-1
2a+2x=18
a+3x=17
a=5
x=4
2b+c+z=11
3b+4c+z=19
3b+6c+5z=43
b=2
c=2
z=5
4(12)+x(4+4)=
6
16x+2x-14= 54
x=5
3c+4u=33
6c+3u=36
c=3
u=6
4a+5c+4u=49
4a+2c+2u=28
4a+3c+6u=45
a=3
c=5
u=3
3