Answer:
Step-by-step explanation:
He had the incorrect slope for the second line, his line has a positive slope of one while the equation has a slope of negative 1.
x+y=1
y=-x+1
He graphed x+1 instead of -x+1
If he graphed them correctly the lines would intersect when the equations were equal
2x+4=-x+1
3x+4=1
3x=-3
x=-1, making y=2x+4 become
y=2(-1)+4
y=2
So the solution was supposed to be the point (-1,2)
