Students plot solutions to linear equations 3x + y = -8 and x - 5y = 11 on a coordinate plane to identify that the graphs are straight lines. They also explain that the graph of -x + 2y = 3 is a straight line based on the linear nature of the equation. Finally, students are challenged to come up with a non-linear equation and plot its solutions to show a non-linear graph.

1. Learning target:
• Students predict the shape of a graph of a linear equation by finding
and plotting solutions on a coordinate plane.
• Students informally explain why the graph of a linear equation is not
curved in terms of solutions to the given linear equation.

2. 1. Find at least ten solutions to the linear equation 3x + y = -8, and plot
the points on a coordinate plane.
x y x y
What shape is the graph of the
linear equation taking?

3. 2. Find at least ten solutions to the linear equation x - 5y = 11, and plot
the points on a coordinate plane.
x y x y
What shape is the graph of the
linear equation taking?

4. 3. Joey predicts that the graph of −x + 2y = 3 will look like the graph shown
below. Do you agree? Explain why or why not.

5. 4. We have looked at some equations that appear to be lines. Can you
write an equation that has solutions that do not form a line? Try to come
up with one and prove your assertion on the coordinate plane.