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171S3.4p Solving Rational Equations and Radical Equations
MAT 171 Precalculus Algebra
Some Media for this Section
Dr. Claude Moore
Cape Fear Community College
CHAPTER 3: Quadratic Functions and Equations; Inequalities
3.1 The Complex Numbers
3.2 Quadratic Equations, Functions, Zeros, and Models
3.3 Analyzing Graphs of Quadratic Functions
3.4 Solving Rational Equations and Radical Equations
3.5 Solving Equations and Inequalities with Absolute Value
Go to SAS Curriculum Pathways, use Subscriber Login and User name: able7oxygen. Explore rational functions and radical functions by using Quick Launch # 1436 at http://www.sascurriculumpathways.com/
October 10, 2012
1. Solving Rational Equations 1 solving simple equations with algebraic fractions. http://cfcc.edu/faculty/cmoore/RationalEquations1.wmv
2. Solving Rational Equations 2 solving more complex equations with algebraic fractions. http://cfcc.edu/faculty/cmoore/RationalEquations2.wmv
3. Solving Radical Equations solving equations with square roots. http://cfcc.edu/faculty/cmoore/SquareRootEquations1.wmv
Watch this very good (9­min) video on solving rational equations. http://www.youtube.com/watch?v=vKakDNh6Q3k
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Example
Solve:
Solution: Multiply both sides by the LCD 6.
3.4 Solving Rational Equations
and Radical Equations
• Solve rational equations.
• Solve radical equations.
Rational Equations ­ Equations containing rational expressions are called rational equations.
The possible solution is 5.
Solving such equations requires multiplying both sides by the least common denominator (LCD) to clear the equation of fractions.
The solution is 5. Oct 4­7:58 PM
TRUE
Oct 4­7:58 PM
1
171S3.4p Solving Rational Equations and Radical Equations
Example
October 10, 2012
Radical Equations
A radical equation is an equation in which variables appear in one or more radicands. For example:
Solve:
Solution: Multiply both sides by the LCD x ­ 3.
The Principle of Powers
For any positive integer n:
If a = b is true, then a n = bn is true.
Solving Radical Equations
The possible solutions are –3 and 3.
Check x = –3:
Check x = 3:
To solve a radical equation we must first isolate the radical on one side of the equation.
Then apply the Principle of Powers.
When a radical equation has two radical terms on one side, we isolate one of them and then use the principle of powers. If, after doing so, a radical terms remains, we repeat these steps.
TRUE
The number ­3 checks, so it is a solution.
Not Defined
Division by 0 is not defined, so 3 is not a solution.
3. Solving Radical Equations solving equations with square roots. http://cfcc.edu/faculty/cmoore/SquareRootEquations1.wmv
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Example
Solve: Solution: First, isolate the radical on one side.
Example
Solve
Solution
Check x = 5:
TRUE
The solution is 5.
The possible solutions are 9 and 2.
Check x = 2.
Check x = 9.
TRUE
FALSE
Since 9 checks but 2 does not, the only solution is 9.
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171S3.4p Solving Rational Equations and Radical Equations
October 10, 2012
Example
Solve: Solution: Graph the two functions and find point of intersection. Follow the screens across from left to right in row one and in row two.
We check the possible solution, 4, on a graphing calculator.
Graph the two functions and find point of intersection.
See instructions for this method at http://cfcc.edu/faculty/cmoore/ti­intersect.htm
Since y1= y2 when x = 4, the number 4 checks. It is the solution.
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Section 3.4 Solving Rational Equations & Radical Equations 281/6. Solve
Section 3.4 Solving Rational Equations & Radical Equations 281/16. Solve
281/19. Solve
281/12. Solve
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171S3.4p Solving Rational Equations and Radical Equations
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Section 3.4 Solving Rational Equations & Radical Equations 281/20. Solve
Problem 281/16.
281/24. Solve
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Section 3.4 Solving Rational Equations & Radical Equations Section 3.4 Solving Rational Equations & Radical Equations 281/34. Solve
281/27. Solve
281/28. Solve
281/38. Solve
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171S3.4p Solving Rational Equations and Radical Equations
October 10, 2012
Section 3.4 Solving Rational Equations & Radical Equations Section 3.4 Solving Rational Equations & Radical Equations 281/48. Solve
282/77. Solve
281/60. Solve
282/78. Solve
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Oct 4­8:59 PM
Section 3.4 Solving Rational Equations & Radical Equations 282/79. Solve
Section 3.4 Solving Rational Equations & Radical Equations 282/81. Solve
282/80. Solve 282/84. Solve
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Oct 4­8:59 PM
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171S3.4p Solving Rational Equations and Radical Equations
October 10, 2012
Section 3.4 Solving Rational Equations & Radical Equations 282/86. Solve
282/88. Solve
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