#1
1. if the difference of the roots 3x^2 - 12 x + c = 0 is 8, find the roots and the value of c.

2. If 2x^2 - 8x + c = 0 has a double root, find the root and the value of c.

help please?
#2
I would help you cuz i think i know this stuff but it's been a while since i've done it. Explain what the root and value thing is and the expression is 8?

Wait you factoring into a binomial

(x-c)(x+c)
Last edited by Phat Stud 55 at Apr 30, 2008,
#3
****
that reminds me
i have algebra to do
its due first block tomorrow
DAMNIT
i have no idea how to do it..
sig under construction.
#4
3x^2 - 12 x + c = 0

(3x-#)(x-#)

You basically have to set it up like that then guess and check. I got:

(3x-9)(x-1), c= +9

You have to do the same thing for the second problem as well

2x^2 - 8x + c = 0

I'd start by factoring out 2 since it's impossible to have a double root with is as coefficient. Just remember to put it back in later.

(x-#)^2 Where 2#=8

Meaning that the number must be four. Plugging it back in gets us:

2(x^2-4x+4) or 2x^2-8x+8

I can't really explain it that well over the internet, but those answers check out.
2 1 1 0
8 1 0 5
0 0 9 6 2 2 5 1
#5
1)Use the formula and get x=-12+-\/144-12c/6
-12+\/144-12c/6-(-12-\/144-12c/6)=8
2(\/144-12c/6)=8
\/144-12c6=4
\/144-12c=24
144-12c=576
-12c=732
c=-36

The roots are:
-12+\/576/6 & -12-\/576/6
-12+24/6 & -12-24/6

x=2
x=-6

Difference=8

2) X=8+-\/64-8c/6
If it has a double root then 64-8c=0
c=8

then 8+-\/0/4=x
x=2

There you go...
Last edited by gonzaw at Apr 30, 2008,