Chapter 7: Problem 53
Perform each indicated operation. Simplify if possible. \(\frac{13}{x^{2}-5 x+6}-\frac{5}{x-3}\)
Short Answer
Expert verified
The simplified expression is \( \frac{-5x + 23}{(x-2)(x-3)} \).
Step by step solution
01
Factor the Denominators
First, factor the quadratic expression in the denominator of the first fraction, \(x^2 - 5x + 6\). Look for two numbers that multiply to 6 and add to -5. These numbers are -2 and -3. Thus, \(x^2 - 5x + 6\) factors to \((x-2)(x-3)\).
02
Write as Single Fraction
Rewrite each fraction with a common denominator. The common denominator for \((x-2)(x-3)\) and \(x-3\) is \((x-2)(x-3)\). For the first term, the denominator is already the common denominator. For the second term, multiply the numerator and denominator by \(x-2\): \[ \frac{5}{x-3} \times \frac{x-2}{x-2} = \frac{5(x-2)}{(x-3)(x-2)} \] Now, write the expression as a single fraction:\[ \frac{13 - 5(x-2)}{(x-2)(x-3)} \]
03
Simplify the Numerator
Simplify the numerator by distributing and combining like terms:\[ 13 - 5(x-2) = 13 - 5x + 10 = -5x + 23 \]So the expression becomes:\[ \frac{-5x + 23}{(x-2)(x-3)} \]
04
Final Simplification
The numerator \(-5x + 23\) does not have common factors with the denominator \((x-2)(x-3)\), so it is already in its simplest form. Therefore, the simplified expression is:\[ \frac{-5x + 23}{(x-2)(x-3)} \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Factoring Polynomials
Polynomials can often be broken down into simpler, easier-to-manage components through a process known as factoring. This is the process of finding which smaller expressions multiply together to produce the polynomial. In our exercise, we deal with the expression \(x^2 - 5x + 6\).
To factor this quadratic, we are looking for two numbers that multiply to +6 (the constant term) and add to -5 (the coefficient of the linear term, x). The numbers -2 and -3 fit these requirements perfectly, because
To factor this quadratic, we are looking for two numbers that multiply to +6 (the constant term) and add to -5 (the coefficient of the linear term, x). The numbers -2 and -3 fit these requirements perfectly, because
- -2 multiplied by -3 equals 6
- -2 plus -3 equals -5
Common Denominators
Finding a common denominator is crucial when performing operations like addition and subtraction on fractions. By finding the same denominator for every term, you can easily combine the fractions into a single expression.
In the exercise, our fractions are \(\frac{13}{(x-2)(x-3)}\) and \(\frac{5}{x-3}\). The first denominator is already \((x-2)(x-3)\).
To develop a common denominator, multiply the numerator and denominator of the second fraction, \(\frac{5}{x-3}\), by \(x-2\):
In the exercise, our fractions are \(\frac{13}{(x-2)(x-3)}\) and \(\frac{5}{x-3}\). The first denominator is already \((x-2)(x-3)\).
To develop a common denominator, multiply the numerator and denominator of the second fraction, \(\frac{5}{x-3}\), by \(x-2\):
- This gives: \(\frac{5(x-2)}{(x-3)(x-2)}\)
- Now, both fractions share the same common denominator: \((x-2)(x-3)\)
Simplifying Fractions
Simplifying fractions is about reducing them to their simplest form, making them easier to work with. To simplify a fraction, any common factors in the numerator and denominator should be canceled out.
After addressing the common denominator, the expression becomes a single fraction: \(\frac{13 - 5(x-2)}{(x-2)(x-3)}\). Simplifying involves first dealing with the numerator:
After addressing the common denominator, the expression becomes a single fraction: \(\frac{13 - 5(x-2)}{(x-2)(x-3)}\). Simplifying involves first dealing with the numerator:
- Distribute the -5 across the \((x-2)\)
- This results in: \(13 - 5x + 10\)
- Combining like terms gives \(-5x + 23\)
Algebraic Operations
Algebraic operations enable us to manipulate and solve equations or expressions using various mathematical rules and processes. These operations typically include:
The operations showcased here highlight how algebra harmoniously combines skills like factoring, distributing, and simplifying fractions to reach a solution.
- Addition and subtraction, as seen in combining terms \(13 - 5(x-2)\)
- Multiplication, for example adjusting denominators and numerators \(5(x-2)\)
- Distribution, used here to expand \(-5(x-2)\) into \(-5x + 10\)
The operations showcased here highlight how algebra harmoniously combines skills like factoring, distributing, and simplifying fractions to reach a solution.