General Question

dotlin's avatar

Having difficulties with algebraic manipulation?

Asked by dotlin (419points) August 6th, 2010

(x+6)(3x^2+9x-5)

x(3x^2+9x-5)
3x^3+9x^2–5x

6(3x^2+9x-5)
18x^2+54x-30

so
3x^3+27x^2+49x-30

um what am I doing wrong?

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14 Answers

dotlin's avatar

I have other but I’ll leave them until this is done

ragingloli's avatar

Worry not, your solution is correct.

dotlin's avatar

But the website is saying it’s wrong the fucking shit website.

ragingloli's avatar

Assign any value to x and compare the results. You will find they are identical.

LuckyGuy's avatar

I got the same answer as you. What is the issue?
(You are wrong about being wrong.)

dotlin's avatar

OK I have one now.
6x(5x-4y)-2x(5y-x)+9xy

-300x^3y+60x^4+240xy^2–48x^3y+9xy

This is just before finally simplifing it if I haven’t made any mistakes.

How do I simply even more.

ragingloli's avatar

@dotlin
I think now you are wrong.
The correct term after removing the brackets is:

30x² – 24xy – 10xy + 2x² + 9xy

after simplifying it, you get

32x² – 25xy

dotlin's avatar

@ragingloli
Oh I was timing 6x into (5x-4y) the same with -2x(5y-x) then timing (30x^2–24xy) by (-10xy+2x^2)

OK.

I know dumb ¬_¬ I know why that’s wrong I just wasn’t thinking.

ragingloli's avatar

@dotlin
As you can see there is a minus sign between the first bracket and the second, that is why you do not multiply the two brackets with each other.

dotlin's avatar

@ragingloli
Yeah I don’t know what I was thinking, now kiss me babe.

Response moderated (Off-Topic)
LostInParadise's avatar

I don’t know what Web site your are using, but WolframAlpha is a site where you can check your work. Just enter your equation. They will tell you a bit more than you need to know, but you will be able to find your answer.

Response moderated (Off-Topic)

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