Question 67078: how do you factor this
2x^2-x-10
Answer by Zoop(21)   (Show Source):
You can put this solution on YOUR website! When factoring a trinomial, simply find two factors of the third term that add to get the second term's coefficient.
For  , these would be the factors of the third term:
-5 * 2
-2 * 5
Obviously, nothing is working, which is an unfortunate side effect of this technique.
So we'll use the British method. The British method requires you to multiply the third time by the coefficient of the first term, which in this case is -10 * 2, -20.
Then, do the same thing you did with the first technique (finding to factors to add to the second term) with this new number, -20.
-5 * 4
-4 * 5
Wouldya look at that! -5 and 4 add to get -1, which is the coefficient of -x.
So now we take -5 and 4 and put both of them over the first term, this time, just without the power.
 and 
Simplify.
and 
Now, just use these and factor.
becomes  , or, 
and
 becomes  , or,  .
Final?
And you're done.
See if that works out for you. =)
-Zoop
|
|
|
