3x-y=6
y=x-4
solve by substitution
3x-x+4=6
2x=2
x=1
Now that you know x, but in in the equation to find y (either equation will work)
y= 1-4
y= -3
now that you have both answers, let's check them.
3(-1) - (-3) =6
yes, it works....
Hopefully this makes sense!
Equation 1.
20÷4=5
0×3=0
5-5=0
Equation 2.
44÷4=11
2×3=6
11-5=6
Equation 3.
56÷4=14
3×3=9
14-5=9