In Exercises 67–82, find each product. (7xy2−10y)(7xy2+10y)
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
0. Review of Algebra
Polynomials Intro
Problem 21
Textbook Question
Multiply or divide as indicated. x2−4x3−8⋅3xx+2
Verified step by step guidance1
Identify the given expression to multiply: \(\frac{\left(x^3 - 8\right)}{\left(x^2 - 4\right)} \cdot \frac{\left(x + 2\right)}{3x}\).
Factor all polynomials where possible. Recognize that \(x^3 - 8\) is a difference of cubes and \(x^2 - 4\) is a difference of squares. Use the formulas: \(a^3 - b^3 = (a - b)(a^2 + ab + b^2)\) and \(a^2 - b^2 = (a - b)(a + b)\).
Rewrite the expression with factored forms: \(\frac{(x - 2)(x^2 + 2x + 4)}{(x - 2)(x + 2)} \cdot \frac{(x + 2)}{3x}\).
Cancel out common factors in the numerator and denominator, such as \((x - 2)\) and \((x + 2)\), to simplify the expression.
Multiply the remaining factors in the numerator and denominator to write the simplified expression as a single fraction.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Polynomial Factoring
Factoring polynomials involves rewriting expressions as products of simpler polynomials. Recognizing special forms like difference of cubes (x³ - 8) and difference of squares (x² - 4) helps simplify expressions before multiplication or division.
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Multiplication and Division of Rational Expressions
When multiplying or dividing rational expressions, factor all numerators and denominators first, then multiply across numerators and denominators. For division, multiply by the reciprocal of the divisor to simplify the expression.
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Rationalizing Denominators
Simplifying Rational Expressions
Simplifying involves canceling common factors in the numerator and denominator after factoring. This reduces the expression to its simplest form, making it easier to interpret or use in further calculations.
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