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Mathematics 7 Online
zarkam21:

Help please on this

zarkam21:

1 attachment
zarkam21:

I already did part I. It is x=1,-2,2

zarkam21:

@Hero @JustSaiyan @Ultrilliam

satellite73:

it is almost impossible to write synthetic division here, but i can try

satellite73:

on the top line list the coefficients of \(x^3-x^2+8x+10\) they are \[\large 3~~-1~~8~~10\]

satellite73:

on the left, put a \(\large 1\)

zarkam21:

I got it I neeed help withanother problem now

zarkam21:

1 attachment
zarkam21:

1 attachment
zarkam21:

@satellite73

satellite73:

part 1. list the numbers that go in to 4 evenly there are 6 of them

satellite73:

you know what they are?q

zarkam21:

I got 1,-2,2

satellite73:

also \(-1,4,-4\)

zarkam21:

OKay got that =)

zarkam21:

NOw part II

satellite73:

unless you meant those are the actual roots part one only asks for the POSSIBLE roots

satellite73:

part two check the easiest number first, that is \(1\) \[f(1)=1-1+4-1=0\] got it on the first try

satellite73:

ok typo there, should have been \[F(1)=1-1+4-4=0\]

zarkam21:

Okay got that =)

satellite73:

so now you know if factors as \[f(x)=x^3-x^2+4x-4=(x-1)(\text{something})\]

zarkam21:

Okay so is this is part of part II as well?

satellite73:

yes, we found one root by checking, we still need to find the others

satellite73:

the easiest way to find the quadratic polynomial is synthetic division, in other words find \[\frac{x^3-x^2+4x-4}{x-1}\]

zarkam21:

Okay so we only found 1 we need to find the rest?

satellite73:

yes

zarkam21:

Okay for -1 it is...

zarkam21:

um I would just put f(-1) and write the rest of the equation right?

satellite73:

no that is not what you should do you should divide like i wrote above

satellite73:

\[\frac{x^3-x^2+4x-4}{x-1}\]

zarkam21:

okay just simply divide

satellite73:

i made another typo, it should be \[\frac{x^3-x^2-4x+4}{x-1}\]

zarkam21:

I got x^2-4

satellite73:

i made another typo it should be \[\frac{x^3-x^2-4x+4}{x-1}\]

satellite73:

yes, you are right

zarkam21:

so would this be part III?

satellite73:

so you have \[x^3-x^2-4x+4=(x-1)(x^2-4)\]

satellite73:

no you are still doing part two, find the other zeros

zarkam21:

ohhhh okay

satellite73:

since \(x^2-4=(x+2)(x-2)\) the other zeros are \(-2\) and \(2\) all three zeros are \[\{-2,1,2\}\]

satellite73:

part three is to factor the polynomial completely which you already did it is \[(x-1)(x-2)(x+2)\]

zarkam21:

okay and then step IV

satellite73:

you have to multiply out to show that it is right, which is silly but not hard

satellite73:

\[(x-1)(x-2)(x+2)=(x-1)(x^2-4)\] is a start

satellite73:

then multiply the last two and see that you get \[x^3-x^2-4x+4\] which you will

zarkam21:

and then is that it?

satellite73:

yes, that is all it asks for

zarkam21:

thank you soooooooo much I really really appreciate it =)

satellite73:

yw

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