7.2 TWO-VARIABLE LINEAR SYSTEMS - （7.2两变量线性系统-）.pdf
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7.2 TWO-VARIABLE LINEAR SYSTEMS
Copyright 漏 Cengage Learning. All rights reserved.
What You Should Learn
鈥 Use the method of elimination to solve systems
of linear equations in two variables.
鈥 Interpret graphically the numbers of solutions of
systems of linear equations in two variables.
鈥 Use systems of linear equations in two variables
to model and solve real-life problems.
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The Method of Elimination
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The Method of Elimination
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Example 2 鈥 Solving a System of Equations by Elimination
Solve the system of linear equations.
Equation 1
Equation 2
Solution:
Multiplying Equation 2 by 4.
Write Equation 1.
Multiply Equation 2 by 4.
Add equations.
Solve for x.
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Example 2 鈥 Solution cont鈥檇
By back-substituting into Equation 1, you can solve
for y.
2x 鈥 4y = 鈥? Write Equation 1.
Substitute for x.
鈥?y = 鈥? Combine like terms.
Solve for y.
The solution is
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Example 2 鈥 Solution c
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