x^2 + 5x - 9
Need to show my work.
I know I start with (x ) (x )
Then is it positive or negative?
(x- ) (x- )
or (x+ )(x+ )
Then I have to get factors of 9, correct?
3 and 3 is all I can come up with, I am soooo confused
2007-06-11 12:38:49 · 6 answers · asked by lexisayn 1 in Education & Reference ➔ Homework Help
Isn't it x^2+6x+9?
If it is...
Yes it is either two negatives or two positives.
For what you put, you can't factor.
But for x^2+6x+9...
YES! YOU CAN FACTOR!
(x-something)(x-something)
No matter what the something is, the middle term will be negative. It is not negative, as we can see. So we can't use that. But we can use the other one.
(x+something)(x+something)
The positive factors (we can only look for positive factors, because the negative one shown above doesn't work) of positive nine are:
3*3 or 9*1
Obvioiusly 9 and 1 won't work (9x+x=10x, not the 6x we are looking for)
So what else is there?
I think you can do that part.
Sorry if you are confused. Factoring is a guess and check thing. You get better the more you do it.
2007-06-11 12:49:15 · answer #1 · answered by Orange Flubb 3 · 0⤊ 0⤋
I believe the first x is positive, and the second is negative.
(x+ )(x- )
Yes, you must find the factors of 9 so it is 3 and 3. So you put a 3 in one side of the parenthesis.
(x+3)(x-3)
Then I believe you must simplify (x+3)(x-3), correct? Or do you just have to leave it at that?
I'm sorry I would help more, but I'm not entirely sure if it's right since I haven't learned that as yet...Hope what I do have so far is helpful. Good luck!
2007-06-11 12:49:11 · answer #2 · answered by 546 2 · 0⤊ 0⤋
When the answer cannot be figure out, it's PRIME, in this case 1&9, and 3&3 can't get 5, so the answer is 5.
2007-06-11 12:54:10 · answer #3 · answered by Anonymous · 0⤊ 0⤋
There are no integers or fractions that are factors. The answer can be obtained by use of the quadratic formula, if you have learned it. If you have not yet studied the quadratic formula, the the problem is probably a typo where they meant 6 instead of 5.
http://www.purplemath.com/modules/quadform.htm
2007-06-11 12:52:48 · answer #4 · answered by meg 7 · 0⤊ 0⤋
3 and -3 give 9; so do 9 and -1, and 1 and -9.
None of these is going to give you 5x though.
Are you sure you have the question written down correctly?
2007-06-11 13:01:24 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Using the quadratic formula we find the roots are:
(5 +/- √61)/2
The roots are irrational so the the original trinomial cannot be factored rationally.
Either you copied the problem wrong, or it's a bad problem.
2007-06-11 12:49:20 · answer #6 · answered by jsardi56 7 · 0⤊ 0⤋