Word Problem! Oh No! Your car has broken down! You don't like walking so you call the local garage to find out what they will charge you to fix it. The mechanic tells you that they charge a flat fee of $100 to use the diagnostic computer to find the trouble plus $30 per hour for labor. a) Write a linear equation that will predict the cost of repairing your car. b) Use the equation to find out how much you will have to pay if the repairs take 6 hours.

Lesson 1.f Write and Solve Systems of Equations. In this section we will … Use technology to solve systems of equations Solve systems of equations by graphing. Solve systems of equations by using substitution and elimination Determine whether a system of equations has one solution, no solutions or infinitely many solutions Set up a system of equations to model a real world situation Find the solution to a real world situation by solving a system of equations

What do you already know about …systems of equations? A system of equations is two or more equations that together define a relationship between variables.

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What does solving a system of equations mean? The solution or solutions are where the lines intersect. There are three types. Parallel lines Intersecting lines Same (Coincident) lines

Graphing Calculator Exercise Solving Systems of Equations using Graphing Calculators

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How do we graph lines? slope-intercept form. Standard Form

Example 1 Where do these lines intersect? 1. Write each equation in slope-intercept form or find the x and y intercepts. 2. Graph both lines 3. Check your solution

Let’s Graph!: Example 2 Where do these lines intersect? x + y = 2 x + y = 6

Example 3: Where do these lines intersect?

Example 4: Where do these lines intersect? x – 2y = 0 y = 2x - 3