First, solve for y (both equations)
x-y= 6
x-6= y
y = x-6
2x+y=3
y= -2x+3
System:
y = x-6 (blue)
y= -2x+3 (red)
Slope intercept form:
y=mx+b
Where:
m= slope ( change of y / change of x )
b= y-intercept ( where the line crosses the y axis)
graph:
The solution is where both equations crosses each other.