Algebra 1 Online!
Henrico County Public Schools, Virginia
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A.4ef
The student will solve multistep linear and quadratic equations in two variables, including
e)  solving systems of two linear equations in two variables algebraically and graphically; and
f)  solving real-world problems involving systems of equations.
Graphing calculators will be used both as a primary tool in solving problems and to verify algebraic solutions.
 Essential Knowledge and Skills Given a system of two linear equations in two variables that has a unique solution, solve the system by substitution or elimination to find the ordered pair which satisfies both equations. Given a system of two linear equations in two variables that has a unique solution, solve the system graphically by identifying the point of intersection. Determine whether a system of two linear equations has one solution, no solution, or infinite solutions. Write a system of two linear equations that models a real-world situation. Interpret and determine the reasonableness of the algebraic or graphical solution of a system of two linear equations that models a real-world situation. Essential Understandings A system of linear equations with exactly one solution is characterized by the graphs of two lines whose intersection is a single point, and the coordinates of this point satisfy both equations. A system of two linear equations with no solution is characterized by the graphs of two lines that are parallel. A system of two linear equations having infinite solutions is characterized by two graphs that coincide (the graphs will appear to be the graph of one line), and the coordinates of all points on  the line satisfy both equations. Systems of two linear equations can be used to model two real-world conditions that must be satisfied simultaneously. Systems of equations can be used as mathematical models for real-world situations. Set builder notation may be used to represent solution sets of equations. The product of the slopes of perpendicular lines is -1 unless one of the lines has an undefined slope.
Vertical Articulation
1. SOL 7.14 - a) solve one- and two-step linear equations; b) solve practical problems in one variable
2. SOL 8.15 - a) solve multistep linear equations in one variable (variable on one and two sides of equations); c) ID properties of operations used to solve
3. SOL AII.4 - solve (algebraically/graphically) a) absolute value equation/inequalities; b) quadratic equations over complex; c) equations containing rational algebraic expression; d) equations containing radical expressions
Instructional Materials
1. VDOE ESS Lesson: Road Trip - Equations and Inequalities (PDF) - Writing equations to describe real-life data; creating statistical plots (Word)
2. VDOE ESS Lesson: Spring Fling Carnival - Equations and Inequalities (PDF) - Writing equations and finding the solutions (intersections) graphically (Word)
3. VDOE ESS Lesson: The Exercise Fields - Equations and Inequalities (PDF) - Setting up a system of equations to solve a real-world problem (Word)
4. VDOE ESS Lesson: How Much Is That Tune? - Equations and Inequalities, Statistics (PDF) - Solving systems of two linear equations in two variables (Word)
5. Notes: Graphing Systems of Equations (ppt)
Real World Lessons
1. Dan Meyer: Playing Catch Up - Who will win?
2. Mathalicious: Flick\$ - Which movie rental service offers the best deal?
Practice
Self-Assessments
Skills
Videos
Explore Learning
1. Modeling Linear Systems - Activity A - Experiment with a system of two lines representing a cat‑and‑mouse chase. Adjust the speeds of the cat and mouse and the head start of the mouse, and immediately see the effects on the graph and on the chase. Connect real‑world meaning to slope, y‑intercept, and the intersection of lines.
2. Solving Linear Systems by Graphing - Compare a system of equations in standard form or in slope‑intercept form to its graph. Examine the graph and table of values. Determine the solutions to the system.
3. Special Types of Solutions to Linear Systems - Compare a system of equations in standard form to its graph. Examine the graph and table of values. Determine the solutions to the system.
4. Systems of Linear Equations - Activity A- Solve a system of linear equations by graphing and finding the intersection of the lines of the equations. Create a system of equations, examine its graph, matrix, and table of values, and determine the solution of the system.
5. Road Trip (Problem Solving) - Plan a cross-country road trip through various U.S. state capitals. First choose a vehicle to drive, and then fill up the tank with gas and go! Find the range and gas mileage of each vehicle, and discover the shortest path between two cities.
Websites
1. Interactive Notes: Solving Systems by Graphing - lessons and practice problems at Regentsprep.org