Name: Date: Period: Systems of Equations & Inequalities Solving by Graphing/Solving by Substitution/ Solving by Elimination/ Solving Special Systems/ Solving Linear Inequalities/ Solving Systems of Linear Inequalities Lessons: 6.1-6.6 Packet 6 Tennessee State Standard SPI 3102.3.9 Solve systems of linear equation/inequalities in two variables. Common Core State Standards A.CED. 2. Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales. A.CED. 3. Represent constraints by equations or inequalities, and by systems of equations and/or inequalities, and interpret solutions as viable or nonviable options in a modeling context. For example, represent inequalities describing nutritional and cost constraints on combinations of different foods. A.REI. 5. Prove that, given a system of two equations in two variables, replacing one equation by the sum of that equation and a multiple of the other produces a system with the same solutions. A.REI. 6. Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables. A.REI. 12. Graph the solutions to a linear inequality in two variables as a half-plane (excluding the boundary in the case of a strict inequality), and graph the solution set to a system of linear inequalities in two variables as the intersection of the corresponding half-planes. 1 Name: Date: Lesson Covered 6-1 Objective: TSW solve systems of linear equations by graphing Period: Skills Covered: graphing linear equations, identifying coordinates Systems of Equations and Inequalities Vocabulary A system of linear equations is __________________________________________________________ _________________________________. A solution of a system of linear equations with two variables is _________________________________________________________________________________. Special Note: If the lines are parallel, there is NO SOLUTION to the system. If the lines are on top of each other (in other words, they are the same line), then EVERY POINT on the line is a solution to the system. Example 1. Tell whether the ordered pair (6, -1) is a solution of the system: 1 𝑦 = 3𝑥 − 3 [ 6𝑥 + 3𝑦 = 12 Example 2. Solve the system by graphing. Check your answer. 3𝑥 + 𝑦 = −8 [ −2𝑥 − 𝑦 = 6 a) Put both lines in slope-intercept form. b) Graph. Use graph paper and a straight edge. BE PRECISE! c) Find point of intersection. Solution always written as ordered pair: ( ___ , ___ ) 2 Name: Lesson Covered: 6-1 Objective: TSW solve systems of linear equations by graphing Date: Skills Covered: graphing linear equations, identifying coordinates Period: Systems of Equations and Inequalities TO SOLVE ON CALCULATOR: After writing both equations in slope-intercept form, push Y= , put the 1st equation in Y1 and the 2nd equation in Y2. Press 2nd TRACE (which is CALC), go to 5:intersect, move the left or right arrows until you are close to the point of intersection, then press ENTER 3 times. At the bottom of the screen the calculator will display the intersection. Part A. 1. Is the ordered pair (-2, 1) a solution of the system: 2𝑥 − 3𝑦 = −7 ? [ 3𝑥 + 𝑦 = −5 2. Solve the system by graphing: −1𝑥 + 12𝑦 = 3 . [ 2 2𝑥 + 3𝑦 = 13 5. Solve the system by graphing: 𝑥 − 2𝑦 = 4 . [ 3𝑥 + 𝑦 = 5 3. Use a graphing calculator to graph and solve the system. −18𝑥 + 6𝑦 = 4 [ 𝑦 = −3.2𝑥 + 2.7 6. To deliver mulch, Lawn & Garden charges $30 per cubic yard plus a $30 delivery fee. Yard Depot charges $25 per cubic yard plus a $55 delivery fee. For how many cubic yards of mulch will the cost be the same? What will that cost be? 3 Name: Lesson Covered: 6-1 Objective: TSW solve systems of linear equations by graphing Date: Skills Covered: graphing linear equations, identifying coordinates Period: Systems of Equations and Inequalities Part B. 1. Is the ordered pair (1, -4) a solution of the system: 𝑥 − 2𝑦 = 8 ? [ 4𝑥 − 𝑦 = 8 5. Solve the system by graphing: 𝑦 = 12𝑥 . [ 𝑥 + 𝑦 = −1 2. Solve the system by graphing: −2𝑥 − 1 = 𝑦 . [ 𝑥 = −𝑦 + 3 3. Use a graphing calculator to graph and solve the system. Round your answer to the nearest tenth. 8 5 𝑥+𝑦 =9 3 [ 5 2 𝑦 = 4𝑥 − 3 6. The baseball team is selling hats. They contacted two companies. Hats Off charges a $50 design fee and $5 per hat. Top Stuff charges a $25 design fee and $6 per hat. A) For how many hats will the cost be the same? B) What is that cost? C) Explain when it is cheaper for the team to use Top Stuff and when it is cheaper to use Hats Off. 4 Name: Lesson Covered: 6-2 TSW solve systems of equations using substitution Date: Skills Covered: solving equations Period: Systems of Equations and Inequalities More Practice! 1. [ 𝑥 − 2𝑦 = 4 𝑥 + 8𝑦 = 16 4𝑥 = 𝑦 − 1 4. [ 6𝑥 − 2𝑦 = −3 2. [ 2𝑥 + 𝑦 = −4 𝑥 + 𝑦 = −7 5. [ 4𝑦 − 5𝑥 = 9 𝑥 − 4𝑦 = 11 5 3. [ 𝑦 =𝑥+3 𝑦 = 2𝑥 + 5 6. One cable TV provider has a $60 setup fee and charges $80 per month, and another provider has a $160 equipment fee and charges $70 per month. A) In how many months will the cost be the same? What will that cost be? B) If you plan to move in 6 months, which is the cheaper option? Explain. Name: Lesson Covered: 6-2 TSW solve systems of equations using substitution Date: Period: Skills Covered: solving equations Systems of Equations and Inequalities Guess what? More Practice 𝑥 + 2𝑦 = 8 𝑥 + 3𝑦 = 12 2. [ 𝑦 = 1.2𝑥 − 4 2.2𝑥 − 𝑦 = −5 5. [ 1. [ 4. [ 𝑥 = 7 − 2𝑦 7. [ 2𝑥 + 𝑦 = 5 –𝑥 + 𝑦 = 4 3𝑥 − 2𝑦 = −7 𝑥 + 2𝑦 = −1 4𝑥 − 4𝑦 = 20 1 2 𝑥 + 13𝑦 = 6 8. [ 𝑥−𝑦 =2 6 3. [ 6. [ 3𝑥 − 𝑦 = 11 5𝑦 − 7𝑥 = 1 2𝑥 + 2𝑦 = 2 −4𝑥 + 4𝑦 = 12 9. A jar contains n nickels and d dimes. There are 20 coins in the jar, and the total value of the coins is $1.40. How many nickels and how many dimes are in the jar? Name: Date: Lesson Covered 6-4 Objective: TSW classify systems of linear equations and determine the number of solutions. Period: Skills Covered: solving equations for a variable and graphing lines Systems of Equations and Inequalities Classify each system. Determine the number of solutions. 𝑦 = −2𝑥 + 5 Example 1. [ 2𝑥 + 𝑦 = 1 𝑦 =𝑥−3 Example 2. [ 𝑥−𝑦−3=0 Example 3. [ −7𝑥 + 𝑦 = −2 7𝑥 − 𝑦 = 2 Example 4. [ 7 3𝑥 + 𝑦 = 2 3𝑥 − 𝑦 = 0 Name: Date: Lesson Covered 6-4 Objective: TSW classify systems of linear equations and determine the number of solutions. Skills Covered: solving equations for a variable and graphing lines Period: Systems of Equations and Inequalities Part B: Classify each system. Determine the number of solutions. 1. [ 4. [ 2𝑥 − 𝑦 = 3 6𝑥 − 3𝑦 = 9 𝑥 + 2𝑦 = −4 𝑦 = −12𝑥 − 4 7. [ 𝑦 = −𝑥 + 5 𝑥+𝑦 =5 2. [ 5. [ 𝑦 = 2𝑥 𝑥 + 𝑦 = −6 −9𝑥 − 3𝑦 = −18 3𝑥 + 𝑦 = 6 3. [ 𝑦 − 1 = 2𝑥 𝑦 = 2𝑥 − 1 6. Matt has $100 in a checking account and deposits $20 per month. Ben has $80 in a checking account and deposits $30 per month. Will the accounts ever have the same balance? Explain. 8. The pep club is selling team buttons. Buttons, Inc. charges $50 plus $1.10 per button, and Logos charges $40 plus $1.10 per button. Write an equation for each company’s cost. Find when the price for both companies is the same. What part of the equation should the pep club negotiate to change so that the cost of Buttons, Inc. is the same as Logos? What part of the equation should change in order to get a better price? 8 Name: Date: Lessons Covered 6-5,6-6 Objective: TSW graph and solve linear inequalities and systems of linear inequalities in 2 variables. Skills Covered: solving equations for a variable and graphing lines Period: Systems of Equations and Inequalities For a system the solution is the half-plane where the shading intersect. Example: Graph the solutions of the inequality: 2𝑥 + 4𝑦 ≤ 8. Solve for y: Solid Line or Dotted Line? Shade Above or Below? 𝑦< 3 𝑥 4 +1 [ 2𝑥 + 3𝑦 ≥ 15 ] −7𝑥 − 4𝑦 ≥ 20 9 Name: Date: Lessons Covered 6-5,6-6 Objective: TSW graph and solve linear inequalities and systems of linear inequalities in 2 variables. Skills Covered: solving equations for a variable and graphing lines Period: Systems of Equations and Inequalities Part A. Graph each system of linear inequalities. 1. [ 𝑦 < 2𝑥 − 1 𝑦>2 2. [ 𝑦 ≥ 3𝑥 3𝑥 + 𝑦 ≥ 3 𝑥<3 𝑦 >𝑥−2 5. [ 𝑥+𝑦 ≤3 𝑦 > 3𝑥 − 4 4. [ 10 Name: Date: Lessons Covered 6-5,6-6 Objective: TSW graph and solve linear inequalities and systems of linear inequalities in 2 variables. Period: Skills Covered: solving equations for a variable and graphing lines Systems of Equations and Inequalities Part B. Graph each system of linear inequalities. 1. [ 𝑦+𝑥 >2 𝑦 ≤ −3𝑥 + 4 4. [ 𝑦 ≤ −3𝑥 − 1 𝑦 ≥ −3𝑥 + 1 2. [ 𝑥 + 5𝑦 > −10 𝑥−𝑦 <4 5. [ 11 𝑦 >𝑥−2 𝑦≤3 Name: Date: 12 Period: