A.
A solution to a pair of equations on a graph is represented when the lines cross each other. Look for the point where p(x) and f(x) cross each other.
p(x) and f(x) cross at (6,2), which is the solution to both equations.
B.
A solution for a singular line is represented by any point that falls on the line. A line will have infinite solutions for infinite x-values.
Two solutions that we can write for f(x) are the points (0, -4) and (4, 0), as the line crosses both points.
C.
This question is exactly the same as part A: a solution to both lines is represented by where they cross.
p(x) and g(x) cross at (3, 6), which is the solution to both equations.