7.2 Two-Variable Linear Systems

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7.2 Two-Variable Linear Systems

• Elimination method

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Solve for (x, y)

• Given the System, I want to reduce the number of
  variables. By multiplying both sides of each
  equation by a number, we can have opposite
  coefficients to add together to eliminate a
  variable.

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Solve for (x, y)

• Given

4
Solve for (x, y)

• Given

Now to find x replace y with 10, in either
equation
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Solve for (x, y)

• Given

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Airplane Speed

• An airplane flying into a headwind travels the
  1800-mile flying distance between Pittsburgh,
  Pennsylvania and Phoenix, Arizona in 3 hour hours
  and 36 minutes. On the return flight, the
  distance is traveled in 3 hours. Find the
  airspeed of the plane and the speed of the wind,
  assuming that both remain constant.

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Airplane Speed

• Airplane travels the 1800-mile in 3 hour hours
  and 36 minutes.
• Return the same distance in 3 hours. Find the
  airspeed, speed of the wind,
• both constant. Write variable for Speeds

Airplane speed r Wind speed w
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Airplane Speed

• Airplane travels the 1800-mile in 3 hour hours
  and 36 minutes.
• Return the same distance in 3 hours.

Airplane speed r Wind speed w
9
Airplane Speed

10
Airplane Speed

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Airplane Speed

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Homework

• Page 495 -498
• 4, 16, 24, 32,
• 40, 48, 49, 63,
• 74, 80

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Homework

• Page 495 -498
• 12, 20, 28, 36,
• 44, 52, 67, 76,
• 82