I forgot How to do these

  • #1
I forgot How to do these....

Homework Statement



y = x^2 - 8x + 10
change into y = (x[plus or minus]A)*(x[plus or minus]B)

I just forgot how to do these.... real fast could someone solve w/ showing work?

Thanks. I just don't remember how to do it.....
 

Answers and Replies

  • #2
1,752
1
You need to find 2 numbers that give you the difference of -8 and the product of positive 10.

Since you won't be able to find it by simple factorization, you have to use the quadratic formula.

Google is your friend!
 
  • #3
Oh ok thanks.

yea, i was just running factors over and over in my head and i wasn't coming up with anything, I'm kind of brain dead, so i wasn't sure if it was just me. Thanks.
 
  • #4
1,752
1
1 and 10
2 and 5

:(
 
  • #5
You need to find 2 numbers that give you the difference of -8 and the product of positive 10.

Since you won't be able to find it by simple factorization, you have to use the quadratic formula.

Google is your friend!
when i type in on Google quadratic formula, then i plug the equations in, it tells me x=16 and x = 8

?????? not the answer i need.
 
  • #6
also those were wrong, i did it wrong. hold on
 
  • #7
1,752
1
Nope ... try it again.
 
  • #8
ok i think i got it, is it just (x - [8+[tex]\sqrt{24}[/tex]/2]) * (x - [8-[tex]\sqrt{24}[/tex]/2])?
 
  • #9
1,752
1
ok i think i got it, is it just (x - [8+[tex]\sqrt{24}[/tex]/2]) * (x - [8-[tex]\sqrt{24}[/tex]/2])?
Yes, but don't forget to reduce!
 
  • #10
by that, you just mean plugging it into a calculator and finding the answer, correct?

which happens to be 6.5505 & 1.4495 correct?
 
  • #11
1,752
1
by that, you just mean plugging it into a calculator and finding the answer, correct?

which happens to be 6.5505 & 1.4495 correct?
No. [tex]\frac{8 \pm \sqrt{4 \cdot 6}}{2}[/tex] can reduce.
 
  • #12
so 4 [tex] \pm \sqrt{2*3} [/tex]?
 
  • #13
1,752
1
Yeppp.
 

Related Threads on I forgot How to do these

  • Last Post
Replies
2
Views
1K
Replies
4
Views
2K
Replies
4
Views
1K
Replies
7
Views
4K
Replies
2
Views
2K
Replies
5
Views
1K
Replies
5
Views
1K
Replies
1
Views
1K
Replies
1
Views
1K
Top