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OpenStudy (anonymous):

find three values of k>0 such that x^2-6x+k can be factored

OpenStudy (anonymous):

@zepdrix

zepdrix (zepdrix):

Ummmm so for it to factor nicely, we need 2 numbers which: `Multiply to k` `Add to -6`

zepdrix (zepdrix):

So ummmm

zepdrix (zepdrix):

Oh I guess it's just as simple as choosing two numbers which add to -6. Then we multiply those numbers to give us k.

zepdrix (zepdrix):

So we could use ummm... how bout, -4+ -2 = -6 right?

OpenStudy (anonymous):

so we need -1 and 6 correct

OpenStudy (anonymous):

or 1*-6

zepdrix (zepdrix):

If we add those values, \[\Large -6+1\ne-6\]Hmm I think you're thinking backwards ^^ heh

OpenStudy (anonymous):

oh i see it needs to equal -6 so yes we can use -4+-2

zepdrix (zepdrix):

If our 2 numbers are -4 and -2, what would our k value be? It should be the product of those two numbers, yes?

OpenStudy (anonymous):

we would get -4+-2=-6

zepdrix (zepdrix):

-4 + -2 = -6 gives us that middle number that we needed. Now to find k, we use the same numbers but we multiply them: -4 * -2 = ?

OpenStudy (anonymous):

8

zepdrix (zepdrix):

Ok good! So there is a value of k>0 that will work for our equation.\[\Large x^2-6x+\color{orangered}{8}\quad=\quad (x-4)(x-2)\]

zepdrix (zepdrix):

So our first answer is k=8. We need to come up with a couple more.

OpenStudy (anonymous):

alright

zepdrix (zepdrix):

One thing to keep in mind, since they're restricting the k value to be positive ( k > 0 ), our numbers will both have to be negative. (Since neg*neg = pos ) Can you think of two other negative numbers that add to -6 besides -4 and -2?

OpenStudy (anonymous):

we could do -2 and-3

zepdrix (zepdrix):

-2 + -3 = -5 Hmm that doesn't quite work.

OpenStudy (anonymous):

1 and 6

OpenStudy (anonymous):

waitt hat dosen't work either

zepdrix (zepdrix):

You're still thinking multiplication silly :3

OpenStudy (anonymous):

3 an3

OpenStudy (anonymous):

-3-3

zepdrix (zepdrix):

good good :) k = -3 * -3

OpenStudy (anonymous):

and that would be 9

zepdrix (zepdrix):

Ok good we've found 2 values! k=8 k=9

OpenStudy (anonymous):

-1-5=-6

zepdrix (zepdrix):

Good good good.

OpenStudy (anonymous):

-1*-5=5

OpenStudy (anonymous):

sorry for thinking multiplication to much lol

zepdrix (zepdrix):

k=5 k=8 k=9 Yayyyy good job \c:/ you found them all!

OpenStudy (anonymous):

thanks for the help

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