Solve a system of equations by graphing

Find system solutions as intersection points of two lines.

Lesson 5

Concept

Graph both equations on the same coordinate plane. Their intersection point is the solution.

Solve y = x + 2 and y = -x + 4 by graphing.

The solution of a graphed system is:

Any point on first line

Any point on second line

Intersection point

Origin only

Parallel lines in a system mean:

One solution

No solution

Infinite solutions

Always (0,0)

These steps are out of order — can you fix them?

1.Locate intersection

2.Write ordered pair

3.Check in both equations

4.Graph both equations

Why should you verify intersection coordinates algebraically?