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Can someone help me with factoring by grouping please do step by step

problem: 3x^2+10x+7

2 Answers

6 votes

Answer:

3x^2 + 10x + 7

1. 3x^2 + 3x + 7x +7

2. 3x(x +1) 7(x+1)

3. (3x + 7)(x+1)

Explanation:

- to factor by grouping, you need an even amount of terms, so to do this you have to split up the middle term, 10x, into two terms. (see step 2)

-to get these numbers, you multiply the coefficents of the first and second term, in this case it would be 3 and 7. When you multiply 3 and 7, you get 21, then you want to find 2 numbers that multiply to 21, but also add up to 10. In this case, it is 7 and 3 again. but it won't always be the originial numbers. ( see step 1)

-then you look at the first two terms, and pull out the common factor, in this case it is 3, you then see what is left over and put it in the parenthesis.

- repeat this again for the second two terms, in this case it is 7. (see step 2)

- you know you have done it right when the numbers in the parenthesis are the same, if they aren't you did it wrong. (see step 2)

- then take the set of numbers in the parenthesis, and the two numbers you are multiplying by, in this case 3x and 7, and those are your factors. (see step 3)

User Neron
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6.7k points
3 votes

Answer:

(3x + 7) (x + 1 )

Explanation:

3x^2+10x+7

first : 3x² is 3x*x

(3x ) (x )

the sign of the constant is positive so it is either (plus *plus or minus*minus)

since the sign of the middle is plus (+10x) and 7 is prime number so it has to be (7*1)

(3x + 7) (x + 1 )

check : multiply 3x(x+1) and 7(x+1)

3x*x +3x*1

7*x +1*7

____________________ add

3x²+ 10x +7 (correct)

User Jakub Jurkian
by
7.0k points