Question 368669: 5c^2-17c+14
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! I'm assuming that you want to factor this right? Please post the full instructions.
Looking at  we can see that the first term is  and the last term is  where the coefficients are 5 and 14 respectively.
Now multiply the first coefficient 5 and the last coefficient 14 to get 70. Now what two numbers multiply to 70 and add to the middle coefficient -17? Let's list all of the factors of 70:
Factors of 70:
1,2,5,7,10,14,35,70
-1,-2,-5,-7,-10,-14,-35,-70 ...List the negative factors as well. This will allow us to find all possible combinations
These factors pair up and multiply to 70
1*70
2*35
5*14
7*10
(-1)*(-70)
(-2)*(-35)
(-5)*(-14)
(-7)*(-10)
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to -17? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -17
| First Number | Second Number | Sum | | 1 | 70 | 1+70=71 | | 2 | 35 | 2+35=37 | | 5 | 14 | 5+14=19 | | 7 | 10 | 7+10=17 | | -1 | -70 | -1+(-70)=-71 | | -2 | -35 | -2+(-35)=-37 | | -5 | -14 | -5+(-14)=-19 | | -7 | -10 | -7+(-10)=-17 |
From this list we can see that -7 and -10 add up to -17 and multiply to 70
Now looking at the expression , replace  with  (notice adds up to . So it is equivalent to )
Now let's factor  by grouping:
 Group like terms
 Factor out the GCF of  out of the first group. Factor out the GCF of  out of the second group
 Since we have a common term of  , we can combine like terms
So factors to
So this also means that factors to (since is equivalent to )
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Answer:
So factors to
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