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Which expression is the factorization of x2 + 10x + 21?

User Ariela
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2 Answers

7 votes

Answer: 12x + 21 or C. F(x) = (x - 2)(x + 2)

Step-by-step explanation:

x2 + 10x + 21

2x + 10x + 21

Rearrange to put the coefficient in front/move it in front of the term.

Ex. (× · 4 ⇒ 4×)

( 7 ) ⇒ 7×)

Identify and group like terms.

(2x + 10x) + 21

Group the coefficients together.

(2+ 10)x + 21

Combine 2 + 10 to get 12.

12x + 21

= 12x + 21

You're Welcome! :))

User Krokodyle
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6.1k points
4 votes

You must remember that a polynomial is written like so...

ax^2 + bx + c

In this case...

a = 1

b = 10

c = 21

To factor you must find two numbers who both add up to b (10) AND multiply to c (21)

3 + 7 = 10

3 * 7 = 21

so...

(x + 3 )(x + 7)

Hope this helped!

~Just a girl in love with Shawn Mendes

User Doctororange
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5.9k points