Use the method described in Exercises 83–86, if applicable, and properties of absolute value to solve each equation or inequality. (Hint: Exercises 99 and 100 can be solved by inspection.) | x2 - 9 | = x + 3
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
Choosing a Method to Solve Quadratics
Problem 47
Textbook Question
Solve each equation. √(3x+7) = 3x+5
Verified step by step guidance1
Start with the given equation: \(\sqrt{3x + 7} = 3x + 5\).
To eliminate the square root, square both sides of the equation: \(\left(\sqrt{3x + 7}\right)^2 = (3x + 5)^2\).
Simplify both sides: \$3x + 7 = (3x + 5)^2$.
Expand the right side using the formula \((a + b)^2 = a^2 + 2ab + b^2\): \$3x + 7 = 9x^2 + 30x + 25$.
Rearrange the equation to set it equal to zero: \$0 = 9x^2 + 30x + 25 - 3x - 7$, then combine like terms to get a quadratic equation.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Solving Radical Equations
Radical equations involve variables inside a root, often a square root. To solve them, isolate the radical expression and then eliminate the root by raising both sides to the appropriate power, typically squaring for square roots. This process can introduce extraneous solutions, so checking all solutions in the original equation is essential.
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Solving Logarithmic Equations
Domain Restrictions
When dealing with square roots, the expression inside the root must be non-negative to produce real numbers. This restriction limits the possible values of the variable, so determining the domain before solving helps avoid invalid solutions and simplifies the solving process.
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Domain Restrictions of Composed Functions
Checking for Extraneous Solutions
Squaring both sides of an equation can introduce solutions that do not satisfy the original equation. After finding potential solutions, substitute them back into the original equation to verify their validity and discard any extraneous solutions.
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Restrictions on Rational Equations
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