SOLUTION: Factoring General Quadratic Trinomial 2x2+x-3 Read 2xsquared plus X minus 3.

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Question 145385This question is from textbook College Algebra: Concepts and Models, Fifth Edition
: Factoring General Quadratic Trinomial 2x2+x-3 Read 2xsquared plus X minus 3. This question is from textbook College Algebra: Concepts and Models, Fifth Edition

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Looking at 2x%5E2%2Bx-3 we can see that the first term is 2x%5E2 and the last term is -3 where the coefficients are 2 and -3 respectively.

Now multiply the first coefficient 2 and the last coefficient -3 to get -6. Now what two numbers multiply to -6 and add to the middle coefficient 1? Let's list all of the factors of -6:



Factors of -6:
1,2,3,6

-1,-2,-3,-6 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to -6
(1)*(-6)
(2)*(-3)
(-1)*(6)
(-2)*(3)

note: remember, the product of a negative and a positive number is a negative number


Now which of these pairs add to 1? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 1

First NumberSecond NumberSum
1-61+(-6)=-5
2-32+(-3)=-1
-16-1+6=5
-23-2+3=1



From this list we can see that -2 and 3 add up to 1 and multiply to -6


Now looking at the expression 2x%5E2%2Bx-3, replace x with -2x%2B3x (notice -2x%2B3x adds up to x. So it is equivalent to x)

2x%5E2%2Bhighlight%28-2x%2B3x%29-3


Now let's factor 2x%5E2-2x%2B3x-3 by grouping:


%282x%5E2-2x%29%2B%283x-3%29 Group like terms


2x%28x-1%29%2B3%28x-1%29 Factor out the GCF of 2x out of the first group. Factor out the GCF of 3 out of the second group


%282x%2B3%29%28x-1%29 Since we have a common term of x-1, we can combine like terms

So 2x%5E2-2x%2B3x-3 factors to %282x%2B3%29%28x-1%29


So this also means that 2x%5E2%2Bx-3 factors to %282x%2B3%29%28x-1%29 (since 2x%5E2%2Bx-3 is equivalent to 2x%5E2-2x%2B3x-3)



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Answer:
So 2x%5E2%2Bx-3 factors to %282x%2B3%29%28x-1%29