๐ Quick Study Guide: Factoring Polynomials with GCF
Factoring polynomials using the Greatest Common Factor (GCF) is a fundamental skill in algebra. It's essentially the reverse of distribution, allowing us to simplify expressions and solve equations.
- ๐ก What is Factoring? It's the process of breaking down a polynomial into a product of simpler polynomials (its factors). Think of it like finding the prime factors of a number, but for algebraic expressions!
- ๐ What is the GCF? The Greatest Common Factor (GCF) of a set of terms is the largest monomial that divides evenly into each term of the polynomial. This includes both numerical coefficients and variable parts.
- ๐ข Steps to Factor using GCF:
- ๐ฏ Step 1: Identify the GCF of Coefficients. Find the largest number that divides into all numerical coefficients.
- ๐ฑ Step 2: Identify the GCF of Variables. For each common variable, take the one with the lowest exponent present in all terms. If a variable isn't in all terms, it's not part of the GCF for variables.
- ๐ Step 3: Combine to Form the Overall GCF. Multiply the GCF of the coefficients by the GCF of the variables.
- โ Step 4: Divide Each Term by the GCF. Perform polynomial division for each term of the original polynomial by the GCF you found.
- ๐ Step 5: Write in Factored Form. The factored form is the $GCF(quotient)$, where 'quotient' is the polynomial you get after dividing each term.
- ๐ Example: Let's factor $6x^2 + 9x$.
- ๐ง Coefficients: 6 and 9. Their GCF is 3.
- ๐ Variables: $x^2$ and $x$. The lowest exponent for $x$ is 1 (from $x^1$). So, the GCF of variables is $x$.
- ๐ Overall GCF: $3 \times x = 3x$.
- โ๏ธ Divide each term: $(6x^2)/(3x) = 2x$ and $(9x)/(3x) = 3$.
- โ
Factored form: $3x(2x+3)$.
๐ง Practice Quiz: Factoring Polynomials
Test your knowledge with these multiple-choice questions!
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Which of the following is the GCF of the polynomial $12x^3 - 18x^2$?
- $3x^2$
- $6x$
- $6x^2$
- $12x^3$
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Factor the polynomial $15a^2b - 20ab^2$.
- $5ab(3a - 4b)$
- $5ab(3a - 4ab)$
- $5ab(3a - 4)$
- $5ab(3a^2 - 4b)$
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What is the completely factored form of $-8y^3 + 4y^2 - 12y$?
- $-4y(2y^2 - y + 3)$
- $4y(-2y^2 + y - 3)$
- $4y(2y^2 - y + 3)$
- $-4y(2y^2 + y - 3)$
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Factor $7m^2n^3 + 21m^3n^2 - 14m^2n^2$.
- $7m^2n^2(n + 3m - 2)$
- $7m^2n^2(n^3 + 3m^3 - 2n^2)$
- $7m^2n^2(n + 3m - 2mn)$
- $7m^2n(n^2 + 3mn - 2n)$
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Which expression represents the factored form of $10x^4 - 25x^3 + 5x^2$?
- $5x^2(2x^2 - 5x)$
- $5x^2(2x^2 - 5x + 1)$
- $5x^2(2x^2 - 5x + x)$
- $5x(2x^3 - 5x^2 + x)$
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If the GCF of $Ax^3 + Bx^2$ is $3x^2$, which of the following could be the values for A and B?
- A=6, B=9
- A=4, B=7
- A=9, B=4
- A=12, B=8
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A rectangular garden has an area given by the polynomial $9x^2y + 15xy^2$ square meters. If the width of the garden is $3xy$ meters, what is the length?
- $3x + 5y$ meters
- $3xy + 5y$ meters
- $6x + 12y$ meters
- $3x^2y + 5xy^2$ meters
Click to see Answers
- C. $6x^2$
- A. $5ab(3a - 4b)$
- A. $-4y(2y^2 - y + 3)$
- A. $7m^2n^2(n + 3m - 2)$
- B. $5x^2(2x^2 - 5x + 1)$
- A. A=6, B=9
- A. $3x + 5y$ meters