Help please

**blizzarddog5** · 08-15-2008, 12:31 AM

(2n^2+9n-56) Factor?
I can't seem to find any number that's a factor of -56 that adds or subtracts to 9... Maybe it's just me, but help?

eh step by step would be nice

**Randmthotz** · 08-15-2008, 12:35 AM

im good at this kinda thing, but i dont have any paper and been a while since i factored in my head

**Randmthotz** · 08-15-2008, 12:39 AM

i know double post, but Blizz, have you covered imaginary numbers yet? if not then you can't actually solve this unless you know them

**blizzarddog5** · 08-15-2008, 12:43 AM

i covered it last year. if ur done let me see steps and ill tell u if i agree or disagree and dont worry this is the void ^^

**AnimeJunky** · 08-15-2008, 12:49 AM

My brain hurts! Is this algebra? I took geometry instead of algebra 2.

Algebra 1 was hard enough.

**Randmthotz** · 08-15-2008, 12:52 AM

haha just looked over some work, made a small mistake with the signs, no imaginary in this, lemme fix/finish and ill post it

**Blaze7** · 08-15-2008, 12:52 AM

Does this help?:
http://www.wtamu.edu/academic/anns/m...28_facttri.htm

**blizzarddog5** · 08-15-2008, 01:02 AM

eh honors pre cal zz =.= no blaze no help i know how to d oit it just seems impossible cause of the numbers

**Randmthotz** · 08-15-2008, 01:09 AM

heres my work, used the quadratic formula.

[-9±[Square root of]81-4(2)(-56)] divided by 4

[-9±[Square root of]81-4(-112)] divided by 4

[-9±[Square root of]81-(-448)] divided by 4

[-9±[Square root of]529] divided by 4

[-9±23] divided by 4

then it splits to:

[-9+23]/4 and [-9-23]/4

14/4 and -32/4

so your answers from that are:

3.5 and -8

So your factored equation would be

(n-3.5)(n+8) i believe

**blizzarddog5** · 08-15-2008, 01:19 AM

hmmm the right side is what i got but i got something different for left side

**Randmthotz** · 08-15-2008, 01:20 AM

i put the equation into a program to check it as well and it came out with the same answer that i got

**blizzarddog5** · 08-15-2008, 01:28 AM

eh thanks random i will try t owork with it and see what i get

**Furanshisu917** · 08-15-2008, 02:59 AM

in algebra u should never get a .5 u always have to have a full number.

no?

**blizzarddog5** · 08-15-2008, 03:19 AM

well pre cal but during factoring it should always be a whole

**hoboX10** · 08-15-2008, 03:37 AM

When it doesn't add or subtract you have to do the formula. I can't really remember it but I think it's:

x=-b(+-Sqrt(b^2-4ac))/2a
Though a couple plus or minuses may be off.

EDIT: (It was b^2MINUS4ac)