This document provides instruction on solving systems of linear equations using substitution and graphing. It gives examples of using substitution to solve systems of equations by solving one equation for one variable and substituting it into the second equation. Students are then asked to solve sample systems of equations using substitution and complete additional practice problems for homework.

1. February 27, 2012
Warm-up:
Graph the following equations.
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2. February 27, 2012
7.1 Linear and Nonlinear
Systems
Essential Question:
How do you use substitution and graphing to solve
systems of equations?
Standard: Linear Algebra 1.0
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3. February 27, 2012
Substitution-
1. Solve one equation for one variable (in terms of the
other).
2. Substitute into the second equation.
3. Solve new equation.
4. Back-substitute to find the other variable.
5. Check solutions in BOTH original equations.
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4. February 27, 2012
Ex. 1) Solve the system by substitution.
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5. February 27, 2012
Ex. 2) Solve the system by substitution.
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6. February 27, 2012
Ex. 3) Solve the system by substitution.
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7. February 27, 2012
Ex. 4) A total of $25,000 is invested in two funds paying
7% and 4% simple interest. The yearly interest is $1405.
How much is invested at each rate?
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8. February 27, 2012
Assignment:
7.1 p. 503 #2, 5, 9,
11, 17, 21, 27, 35, 67
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