Answer: a. The x-coordinate of the intersection point.
If you solve an equation by graphing each side of the equation, the x-coordinate of the point where the graphs intersect gives the solution of the equation.
Answer: c. Two identical lines.
Graphing each side of an identity will result in two identical lines. Since these lines intersect at every possible value of x, the equation is true for all values of x.
Answer: b. The intersection point on each graph will have the same x-coordinate.
If you subtract the same number from both sides of an equation, you do not change the solution of the equation. For equations with a single solution, the x-coordinate of the intersection will be the same on both graphs. Only the y-coordinate of the intersection point will change.