Lesson: Systems of Equations Part I: Graphing

​Systems of Equations, Part I
Solve by Graphing

​

More than one equation that share a solution.

​

​What is a "System of Equations?"

​We want to find one point that is on both lines. That will be a solution to both equations.

​For each equation:

1. Graph the y-intercept
2. Use the Slope to make another point
3. Graph the line.

​The lines cross at (1,2). That should be the solution to both equations.
To check, insert the (x,y) into each equation.

2 = -2 (1) + 4


2 = -(1) + 3

Multiple Choice

Which graph shows a solution to the system of equations:

y = 2x - 3

y = 2/3x +1

The two equations will have the same slope but a different y-intercept. NOTE: They will be parallell!

No Solution

This means that the two equations have the same slope AND the same y-intercept.

​Infinitely Many

Other possible solutions to systems of Equations:

Multiple Choice

What is the solution to the two equations graphed?

• Infinitely Many

• (0, 3)

• No Solution

• (0, -1)

Poll

How will you know if two equations share an infinite number of solutions?

• They never touch.

• They are graphed right on top of one another

• They cross at two points

• They cross at only one point

​Final tip: When graphing by hand, use a straight edge! If your lines are crooked, you won't find the right spot where they meet. After this lesson, Mrs. Black will show you how to make your own straight edge. Now go to Google Classroom to get the IXL to practice this skill.