## Firejay5 3 years ago Simplify. Use long division to solve. Subtract your answers, NOT add 10. (x^3 + 13x^2 - 12x - 8) / (x + 2)

1. Firejay5

My answer is -72, but I don't know what to do next

2. Australopithecus

3. .Sam.

Setup the long division as follows, solve by dividing . (x^3 + 13x^2 - 12x - 8) with (x + 2)

4. Australopithecus

it teaches you long division of polynomials

5. Australopithecus

6. Australopithecus

what ever remainder you have left you have to keep it divided by x + 2

7. Firejay5

I know how to do it, it's just I don't know if I put it over x + 2 ----> $\frac{ x + 2 }{ -72 }$

8. .Sam.

What do you have for your long division?

9. Australopithecus

x+2 remains in the denominator and it should be 60

10. Australopithecus

I'm pretty sure based on wolfram alphas answer

11. Firejay5

@.Sam. so far

12. .Sam.

13. Firejay5

I know that; it's just I need help with where the -72 goes and @Australopithecus it's not 60

14. .Sam.

@Firejay5 the remainder is 60

15. Firejay5

No it's not it's -72 I did my work

16. .Sam.

Try check your work with this,

17. Firejay5

It's -76

18. Firejay5

when you subtract; it's like you're distributing - into the second equation http://assets.openstudy.com/updates/attachments/50875f3ae4b058e80cf64652-.sam.-1351050109514-2.png

19. Firejay5

Like when you are subtracting 11x^2 - 12x - (11x^2 + 22x)

20. Firejay5

you are are trying to cancel and get rid of the 11x^2

21. .Sam.

yes, then you get -34 x

22. Firejay5

It should be -34x - 8 - (34x + 68)

23. .Sam.

-34 x 2 = -68

24. .Sam.

its not +68 but its -68

25. Firejay5

what's -8 - 68

26. .Sam.

You should be careful there, its actually -8-(-68)

27. Firejay5

Are you getting confused??? @.Sam.

28. .Sam.

don't memorize the facts, just remember that it is top minus the bottom, you look back the previous steps, all you do is to subtract the top one with the bottom one, the steps that I gave you is computer generated, its completely true.

29. Firejay5

you have to apply the negative -(34x + 68) to all number s in parentheses

30. Australopithecus

a remainder is just part of the equation that you cannot divide, so it is left with the denominator so in your case 60/(x+2)

31. .Sam.

The actual answer is 60, why are you ignoring it? Take a look at the picture below.

32. Australopithecus

I'm basing my 60/(x+2) on the wolfram alpha simplification

33. Firejay5

It's not -34x - 68 it's -(34x + 68) the minus/negative in front of the parentheses goes with everything in it