Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
4. Factoring Quadratic Expressions
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Exercise 19 Page 221

Is there a greatest common factor between all of the terms in the given expression? If so, you should factor that out first.

(x+2)(x+20)

Practice makes perfect
To factor a trinomial with a leading coefficient of 1, think of the process as multiplying two binomials in reverse. Let's start by taking a look at the constant term. x^2+22x+ 40 In this case, we have 40. This is a positive number, so for the product of the constant terms in the factors to be positive, these constants must have the same sign (both positive or both negative).
Constants Product of Constants
1 and 40 or -1 and - 40 40
2 and 20 or -2 and - 20 40
4 and 10 or -4 and - 10 40
5 and 8 or -5 and - 8 40

Next, let's consider the coefficient of the linear term. x^2+ 22x+ 40 For this term, we need the sum of the factors that produced the constant term to equal the coefficient of the linear term, 22. We will be checking each pair until we get this result.

Constants Sum of Constants
1 and 40 41
-1 and -40 -41
2 and 20 22
We found the factors whose product is 40 and whose sum is 22. x^2+ 22x+ 40 ⇔ (x+2)(x+20)

Checking Our Answer

Check your answer âś“
We can check our answer by applying the Distributive Property and comparing the result with the given expression.
(x+2) (x+20)
x(x+20)+2(x+20)
x^2+20x+2(x+20)
x^2+20x+2x+40
x^2+22x+40
After applying the Distributive Property and simplifying, the result is the same as the given expression. Therefore, we can be sure our solution is correct!