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3 votes
How do you know what to put first when you factor in for example

5x^2+7x+2

1 Answer

4 votes

Answer:

(x + 1)(5x + 2)

Explanation:

5x² + 7x + 2

consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term.

product = 5 × 2 = 10 and sum = + 7

the required factors are + 5 and + 2

use these factors to split the x- term.

5x² + 5x + 2x + 2 ( factorise the first/second and third/fourth terms )

= 5x(x + 1) + 2(x + 1) ← factor out (x + 1) from each term

= (x + 1)(5x + 2)

since multiplication is commutative, that is a × b = b× a , then

factored form is either

(x + 1)(5x + 2) or (5x + 2)(x + 1)

User Anatolii Gabuza
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