To factor out the common factor of each polynomial, you identify the greatest common factor (GCF) shared by all terms and then rewrite the polynomial using the distributive property.
Here's a breakdown of the process:
1. Identify the Greatest Common Factor (GCF)
- Look at the coefficients (numbers in front of the variables): Find the largest number that divides evenly into all the coefficients.
- Look at the variables: Identify the variable(s) common to all terms. Determine the lowest exponent of each common variable that appears in all terms.
- Combine: The GCF is the product of the largest common numerical factor and the lowest power of the common variable(s).
2. Apply the Distributive Property in Reverse
- Divide each term in the polynomial by the GCF you found.
- Rewrite the polynomial as the GCF multiplied by the expression resulting from the division in the previous step. This uses the distributive property in reverse:
a*b + a*c = a*(b + c)
Example 1
Factor out the common factor of the polynomial: 6x^2 + 9x
-
Identify the GCF:
- Coefficients: The largest number that divides evenly into both 6 and 9 is 3.
- Variables: Both terms have
x
. The lowest exponent ofx
is 1 (in9x
). - GCF:
3x
-
Apply the distributive property in reverse:
- Divide each term by
3x
:6x^2 / 3x = 2x
9x / 3x = 3
- Rewrite the polynomial:
6x^2 + 9x = 3x(2x + 3)
- Divide each term by
Example 2
Factor out the common factor of the polynomial: 12a^3b^2 - 18a^2b^4 + 30a^4b^3
-
Identify the GCF:
- Coefficients: The largest number that divides evenly into 12, -18, and 30 is 6.
- Variables: All terms have
a
andb
. The lowest exponent ofa
is 2 and ofb
is 2. - GCF:
6a^2b^2
-
Apply the distributive property in reverse:
- Divide each term by
6a^2b^2
:12a^3b^2 / 6a^2b^2 = 2a
-18a^2b^4 / 6a^2b^2 = -3b^2
30a^4b^3 / 6a^2b^2 = 5a^2b
- Rewrite the polynomial:
12a^3b^2 - 18a^2b^4 + 30a^4b^3 = 6a^2b^2(2a - 3b^2 + 5a^2b)
- Divide each term by
Summary
Factoring out the common factor involves finding the GCF of all terms in a polynomial and then using the distributive property in reverse to rewrite the polynomial as the GCF multiplied by a new polynomial expression. This simplifies the original polynomial and can be useful for solving equations and simplifying expressions.