In this program students learn to write the equations of parallel and perpendicular lines. Instructor: Cryshel Whitehead (The transcript of this program is available for download at the link below.)

This example shows an elimination by addition method that can be used to solve a system of equations.

This module shows how to use the substitution method to solve for x and y.

Learn how an architect uses scale drawing and other mathematics to represent floor plans of buildings under construction in this video from MPT. In the accompanying classroom activity, students watch the video and then create a scale drawing of a rectangular area in or near the classroom, choosing an appropriate scale and explaining their strategies for calculating scaled measurements. In the process, they are exposed to an algebraic strategy for calculating dimensions to scale. To get the most from the lesson, students should have experience solving equations of the form ax = b. For a longer self-paced student tutorial using this media, see "Solving Linear Equations" on *Thinkport* from Maryland Public Television.

Practice solving equations with variables on both sides.

Practice solving systems of equations by substitution.

Learn about the role of math in architecture in this media gallery from MPT. In the accompanying classroom activity, students design a triangular roof and find equations for the lines that include the sides of the triangle. They verify that the point at which the two lines intersect satisfy both equations. To get the most from the lesson, students should be comfortable finding the equation of a line from two points and graphing linear equations, and they should be familiar with slope and y-intercept. For a longer self-paced student tutorial using this media, see "Systems of Equations" on *Thinkport* from Maryland Public Television.

Work through an example of solving a system of equations with elimination by additions.

Write a linear equation to answer the question, "How old is Ben now?"

In this video, explore linear equations in one variable with one solution, infinitely many solutions, or no solutions. In the accompanying classroom activity, students watch the video and then write and solve three equations: one with one solution, one with infinitely many solutions, and one with no solutions. They trade with a partner and solve each other’s equations. To get the most from this lesson, students should be comfortable solving linear equations in one variable with one solution.