Binomial Factors: 7k^2 - 9k - 10, 4n^2 -5n - 6, etc

A

aj923

New member
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Jun 20, 2007
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Yes I'm having trouble finding the binomial factors for trinomials. Problems such as these are giving me trouble:

1) 7k^2 - 9k - 10

2) 10m^2+ 11m - 6

3) 4n^2 -5n - 6

Thanks in advance for any help you can provide.
also could u help with higher degree binomials.
 
Hello there:

I will step through one and you try the others. Okey-doke?.

\(\displaystyle \L\\7k^{2}-9k-10\)

Try finding two numbers which when added equal -9 and when multiplied equal -70 (because the leading coefficient is 7 and 7*-10=-70).

How about -14 and 5.

\(\displaystyle \L\\7k^{2}-14k+5k-10\)

Factor out something common:

\(\displaystyle \L\\7k(k-2)+5(k-2)\)

\(\displaystyle \L\\(7k+5)(k-2)\)

Voila!

Now, you try the others and write back if you're stuck.
 
Do you have the quadratic formula?
Can you complete the square?
How are your skills at finding factors of integers?

Without any effort shown in your post, it is difficult to judge where you are. Answer those questions, show some of your efforts, and we can talk.
 
thanks

Thanks for the help. I tried the 4n^2 - 5n - 6. But I still get the same answer that I was getting all day yester day: which is (2n- 3/4)(2n + 2) but i've been told thats wrong.
 
What two numbers when multiplied equal -24 and when added equal -5?.

How about -8 and 3?. Now continue.
 
so all u have to do is see what 2 numbers multiply to give you the last number that add to give you the middle number? if thats the case thanks.
 
so all u have to do is see what 2 numbers multiply to give you the last number ....
Click to expand...

No..

It is product of two numbers that gives you the product of the first term and the last term.

Like in case of

6n^2 +5n - 4

You chose 8 and -3 because 8*-3 = -24 and 6*-4 = -24

The pair also has to satisfy the oher condition also, i.e., added together they give you the middle number.
 
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