I have to find 2 integers...

P

pgfreak

New member
Joined
Oct 15, 2006
Messages
9
I got stuck after the first few steps... heres the question : Find two integers whose sum is 89 and whose product is 1824.

for my work, so far I had...

(let x represent one integer and y the other)
x+y=80
xy= 1824

so... x=80-y
y(80-y)=1824
80y-y^2=1824
0=y^2-80y+1824 ..... ya I dont even know if I did up to there right.. help please!
 
Looks real good point gaurd freak!


Factor you polynomiall:\(\displaystyle \L \;0\,=\,y^2\,-\,89y\,+\,1824\)
 
how'd you know it was point guard??

how would I factor that farther?? :? factor out a y?

so something like...
=y(y-80) +1824
=y(y -80 +1600-1600)+1824
=y(y-80+1600) -1600y+1824
=y( ..............wait this cant work... what did I do wrong... I cant factor out that y can I?

(i have half a mind to use the quadratic formula for this (the -b+/-..... formula) but i dont think I'm supposed to use that to get the answer)
 
Does the problem say a certain method?
Click to expand...

Its just part of a quadratic funtions thing. I'm guessing we cna use quadratic formula or get the x and y intercept ubt I dont know how that would help... Using the quadratic formula wont even work, look
under the square root sign I'll get...
(-80)^2-4(1)(1824)
=6400-7296
=-896

and if its a negative under the square root sign then its not possible... :? Am I supposed to use the different method to get the x-y intercept?
 
x+y=80
Click to expand...

This should be: x + y = 89

Edit: Ok I have a very primitve method for solving this.

I made a factor tree to see all the factors of 1824.

Then I went through the factors and found two that muliplied to give me 1824 and added up to - 89.

I found -57 and - 32.

............So now solve:\(\displaystyle \L \;(y\,-\,32)\,(y\,-\,57)\,=\,0\)

It works, I checked it, and have a great night! :D
 
added up to - 89.
Click to expand...

the question asked for 89, not -89... ugh see one dumb number/sign can change it all, its soo frustrating, but I think me writing 80 instead of 89 might have been the thing that threw me off so I'll try it again.
 
pgfreak said:
the question asked for 89, not -89... ugh see one dumb number/sign can change it all, its soo frustrating, but I think me writing 80 instead of 89 might have been the thing that threw me off so I'll try it again.
Click to expand...

This works. Take a look:

89y - y^2 = 1824

Subtract 1824: -y^2 + 89y - 1824 = 0

Divide by - 1: y^2 - 89y + 1824 = 0

So what I did was correct.
 
pgfreak said:
heres the question : Find two integers whose sum is 89 and whose product is 1824.
Click to expand...

Boy oh boy...keep it simple!

xy = 1824; so y = 1824/x

x + y = 89
x - 89 + 1824/x = 0 ; multiply by x to get rid of fraction:
x^2 - 89x + 1824 = 0
Use quadratic:
x = [89 +- sqrt(89^2 - 4(1824))] / 2
x = (89 +- 25) / 2
x = 57 or 32

Best point guard is Steve Nash :wink:
 
Yes Denis thank you, you too jonboy!!
and I like Iverson personally :wink: ,but I do agree that Nash is a GREAT point guard and once again, they're gunna have a nice team, specially because of amare and I think they have jumaine jones now so hes a good replacement for the loss of tim thomas
 
My grandson Tyler will be the next Canadian to go down there and take over!
In his first league game as a Midget (14,15's) yesterday, he had 12 points,
3 assists, 6 rebounds and 5 steals: all in 16 minutes.
Last year, he had a 29 points game; 16 minutes again.
 
You must log in or register to reply here.
Top