A solution to the two equations is a point that is on both lines. That point is the point of intersection of the lines. There is one point of intersection of the lines, so that point is the solution.
Answer: There is 1 solution.
Part B.
The solution is the point of intersection of the lines. We see where the lines intersect, and we read the point of intersection of the graph. The point of intersection is (4, 4).
Jack's method is equivalent because of the "law of commutative property", which means that multiplication problems have the same result no matter the order.