Word Problem!

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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.
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• a) Write a linear equation that will predict the
  cost of repairing your car.
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• b) Use the equation to find out how much you
  will have to pay if the repairs take 6 hours.

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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

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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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Video!!! In Common

• http//www.youtube.com/watch?featureplayer_detail
  pagevBr7qn4yLf-I

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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
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Graphing Calculator Exercise

• Solving Systems of Equations using Graphing
  Calculators

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You try
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How do we graph lines?

• slope-intercept form.

• Standard Form

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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

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Lets Graph! Example 2Where do these lines
intersect?

• x y 2
• x y 6

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Example 3 Where do these lines intersect?

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Example 4Where do these lines intersect?

• x 2y 0
• y 2x - 3