Why is he wrong? What is the correct 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)

the answer is d. (1.2, -4.7) on edgn

hope this !