Chapter 7: Problem 31
In the following exercises, multiply the rational expressions. $$ \frac{5 x^{2} y^{4}}{12 x y^{3}} \cdot \frac{6 x^{2}}{20 y^{2}} $$
Short Answer
Expert verified
\(\frac{x^{3}}{8 y}\)
Step by step solution
01
- Multiply the Numerators
First, multiply the numerators of the given fractions: \[5 x^{2} y^{4} \times 6 x^{2} = 30 x^{4} y^{4}\]
02
- Multiply the Denominators
Next, multiply the denominators of the given fractions: \[12 x y^{3} \times 20 y^{2} = 240 x y^{5}\]
03
- Combine the Fractions
Combine the results from Step 1 and Step 2 into a single rational expression: \[\frac{30 x^{4} y^{4}}{240 x y^{5}}\]
04
- Simplify the Coefficients
Simplify the coefficients (numerical parts) of the fraction: \[\frac{30}{240} = \frac{1}{8}\]
05
- Simplify the Variables
Simplify the variables in both the numerator and the denominator: \[\frac{x^{4}}{x} \cdot \frac{y^{4}}{y^{5}} = x^{4-1} \cdot y^{4-5} = x^{3} y^{-1}\]
06
- Finalize the Expression
Combine the simplified coefficients and variables together: \[\frac{1}{8} x^{3} y^{-1}\]This simplifies further to: \[\frac{x^{3}}{8 y}\]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
rational expressions
A rational expression is a fraction where both the numerator and the denominator are polynomials. Polynomials can include variables, coefficients, and constants combined using addition, subtraction, multiplication, and non-negative integer exponents. Understanding rational expressions is important because they show up frequently in algebra, and knowing how to manipulate them will help solve more complex algebraic equations.
Example of a rational expression: \( \frac{3x^2 + 2x - 5}{x^2 - 1} \)
Example of a rational expression: \( \frac{3x^2 + 2x - 5}{x^2 - 1} \)
simplifying variables
Simplifying variables means reducing the expression to its simplest form by canceling out the common factors in the numerator and the denominator. When simplifying variables, follow these steps:
So, \ \frac{x^3}{8y} \ is the simplified form.
- Identify common variables in both the numerator and the denominator.
- Subtract the exponent in the denominator from the exponent in the numerator for each variable.
- If the result is a positive exponent, the variable remains in the numerator; if negative, it remains in the denominator.
So, \ \frac{x^3}{8y} \ is the simplified form.
multiplying fractions
Multiplying fractions is straightforward. You multiply the numerators together to get the new numerator and the denominators together to get the new denominator.
- Multiply the numerators: \( 5x^2y^4 \times 6x^2 = 30x^4y^4 \).
- Multiply the denominators: \( 12xy^3 \times 20y^2 = 240xy^5 \).
- Combine them into one fraction: \( \frac{30x^4y^4}{240xy^5} \).
algebraic fractions
Algebraic fractions are fractions where the numerator and/or the denominator contain algebraic expressions. They function similarly to regular fractions, but with the added step of dealing with variables.
Here's how you handle them:
Here's how you handle them:
- Perform operations (addition, subtraction, multiplication, or division) as you would with numerical fractions.
- Ensure the expressions are in their simplest form by factoring where possible.
- Remember the basic rules of exponents when multiplying or dividing terms.