Chapter 5: Problem 103
Factor each polynomial completely. $$ -2 w^{2}+18 w+20 $$
Short Answer
Expert verified
\( -2(w - 10)(w + 1) \)
Step by step solution
01
- Identify the Greatest Common Factor
Look for the greatest common factor (GCF) of the given polynomial terms \( -2w^2, 18w, \text{and} 20 \). The GCF for these terms is \( 2 \).
02
- Factor Out the GCF
Factor out \( -2 \) from each term: \( -2(w^2 - 9w - 10) \).
03
- Factor the Remaining Quadratic Expression
Rewrite the quadratic expression inside the parentheses: \( -2(w^2 - 9w - 10) \). We need to find two numbers that multiply to \(-10\) and add up to \(-9\). These numbers are \( -10 \) and \( 1 \).
04
- Write the Factored Form
Use the numbers found in Step 3 to write the factored form of the quadratic: \( -2(w - 10)(w + 1) \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
headline of the respective core concept
Identifying the greatest common factor (GCF) is a crucial step in factoring polynomials. The GCF is the largest factor that divides all the terms in a polynomial. For the given polynomial \( -2w^2 + 18w + 20 \), the terms are \( -2w^2 \), \( 18w \), and \( 20 \). To determine the GCF, follow these steps:
By factoring out the GCF, you simplify the polynomial, making it easier to work with in later steps. In this exercise, after identifying the GCF, we factored it out:
\( -2w^2 + 18w + 20 = -2( w^2 - 9w - 10 ) \)
- List the factors of each term.
- For \( -2w^2 \): the factors are \( -2, w, w \).
- For \( 18w \): the factors are \( 2, 3, 3, w \).
- For \( 20 \): the factors are \( 2, 2, 5 \).
- Identify the common factors across all terms: In this case, it’s just \( 2 \).
- The GCF is \( 2 \).
By factoring out the GCF, you simplify the polynomial, making it easier to work with in later steps. In this exercise, after identifying the GCF, we factored it out:
\( -2w^2 + 18w + 20 = -2( w^2 - 9w - 10 ) \)
headline of the respective core concept
A quadratic expression is a polynomial of degree 2, generally written in the form \( ax^2 + bx + c \). For this specific problem:
Thus, the quadratic expression \( w^2 - 9w - 10 \) can be factored into \( (w - 10)(w + 1) \).
- We have the quadratic expression inside the parentheses: \( w^2 - 9w - 10 \).
- The standard form here is with \( a = 1 \), \( b = -9 \), and \( c = -10 \).
- To factor it, we need to find two numbers that:
- Multiply together to \( ac \), which is \( 1 * -10 = -10 \)
- Add up to \( b \), which is \( -9 \).
- Those two numbers are \( -10 \) and \( 1 \), because:
- \( -10 * 1 = -10 \)
- \( -10 + 1 = -9 \)
Thus, the quadratic expression \( w^2 - 9w - 10 \) can be factored into \( (w - 10)(w + 1) \).
headline of the respective core concept
To express a polynomial in its factored form means to write it as a product of simpler expressions. After identifying and factoring out the greatest common factor and handling the quadratic expression, the final steps are straightforward:
Understanding these steps is crucial for moving forward in algebra, as factoring polynomials is a foundational skill in solving various types of algebraic equations. Once you have the polynomial in factored form, you can use it for solving equations, graphing parabolas, and more.
- From our given polynomial \( -2w^2 + 18w + 20 \), we factored out \( -2 \). Thus, we have: \( -2(w^2 - 9w - 10) \).
- Next, we factored the quadratic expression \( w^2 - 9w - 10 \) into \( (w - 10)(w + 1) \).
- Putting it all together, the complete factored form of the polynomial is: \( -2(w - 10)(w + 1) \).
Understanding these steps is crucial for moving forward in algebra, as factoring polynomials is a foundational skill in solving various types of algebraic equations. Once you have the polynomial in factored form, you can use it for solving equations, graphing parabolas, and more.