## anonymous 5 years ago Please help me, simplify, leave in exponent form 5(rt)^9

1. anonymous

Expand, then simplify. Eventually you'll be able to do the simple way, but for now lets keep with the basics.

2. anonymous

If you want to have someone check your answer please post the answer you got and ask for a check. Just posting the problem makes it appear as though you're not doing the work or understanding the material which makes people tend to not want to continue helping. If you show that you've done it and you just want to be sure you're correct people are more than happy to confirm.

3. anonymous

so r*r*r*r*r*r*r*r*r t*t*t*t*t*t*t*t*t

4. anonymous

i still dont understand i get some of the problems but a few of them like this and the last I just cant figure out

5. anonymous

It's ok. you're doing really well. $5(rt)^9 = 5(rt)(rt)(rt)(rt)(rt)(rt)(rt)(rt)(rt)$ $=5rrrrrrrrrttttttttt$ Right?

6. anonymous

yes so 5r^9t^9?

7. anonymous

yes.

8. anonymous

yayyy, can you explain the FOIL method to me?

9. anonymous

Sure. You know that a(b+c) = ab + ac Right?

10. anonymous

yes so like (3x-6)(x-12) = 4x+18

11. anonymous

That's jumping ahead, and not quite correct. Lets back up a step.

12. anonymous

haha ok sorry

13. anonymous

4(x + 3) = ?

14. anonymous

4x+12?

15. anonymous

Right. But we know that 4 is 3 + 1, so we should get the same thing if we rewrite it as (3+1)(x+3)

16. anonymous

So lets take that whole first factor and multiply it by each of the terms in the second factor $\rightarrow (3+1)(x+3) = (3+1)x + (3+1)3$

17. anonymous

And then we distribute again.. $(3+1)x+(3+1)3 = 3x + 1x + 9 + 3$

18. anonymous

$= 4x+12$

19. anonymous

sorry had to step away for a moment

20. anonymous

=4x+12?

21. anonymous

So now if we have something like: (a+b)(c+d) we can distribute: $(a+b)(c+d) = (a+b)c + (a+b)d = ac + bc + ad + bd$

22. anonymous

But to make it easy to remember they prefer you to use FOIL which does the same thing, but in a different order.

23. anonymous

+bd

24. anonymous

i have like 5 sections and the first says use the foil and the rest just says find the product

25. anonymous

(a+b)(c+d) They take the F irst two terms(a and c) O uter two terms(a and d) I nner two terms (b and c) L ast two terms (b and d) ac + ad + bc + bd Which is the same as what we had, but with a slightly different order.

26. anonymous

oh okay im going to work a problem really quick can you check my answer?

27. anonymous

yep

28. anonymous

(3x-6)(x-12) 4x+3x-12-6x+18

29. anonymous

Afraid not. (3x-6)(x-12) Multiply the F irst two terms (3x and x) 3x * x = ?

30. anonymous

4x

31. anonymous

Nope. 4x = 3x + x

32. anonymous

3x^2

33. anonymous

Correct. Now the I nner two terms (-6 and x) -6 * x = ?

34. anonymous

-6x

35. anonymous

Now the O uter two terms(-6 and -12) -6 * -12 = ?

36. anonymous

72

37. anonymous

Blah! Those are not the outer terms, they're the Last terms. Sorry.

38. anonymous

Now the O uter two terms(3x and -12) 3x * -12 = ?

39. anonymous

is it -36x? or does it say the same since they are not like terms?

40. anonymous

it is -36x, just like -6 * x was -6x.

41. anonymous

You can rearrange the factors of a product. a*b*c = a*c*b = b*c*a = c*a*b = ... etc

42. anonymous

so now i have: 3x^2-6x^36x+72?

43. anonymous

yes, except that it's -6x-36x, not -6x^36x but I think that was a typo.

44. anonymous

yes sorry so now it is 33?

45. anonymous

-6-36 = ?

46. anonymous

-42

47. anonymous

so -6x-36x = x(-6-36) = ?

48. anonymous

x(-42)

49. anonymous

So $3x^2 - 6x - 36x - 72 = ?$

50. anonymous

i thought i had the answer, im never going to get through college :( 3x^2-x(-42)-72

51. anonymous

You're really close. The only problem is you left an extra - there.

52. anonymous

before 72?

53. anonymous

We said that -6x-36x = x(-42) which we can re-arrange to be -42x So 3x^2 -6x -36x - 72 = 3x^2 -42x - 72

54. anonymous

ohh man im never going to pass, im sorry you had to take your free time to help me. thank you so much im just having the hardest time

55. anonymous

no you're doing great Think about it like this. If you have 4x's and you subtract 36x's you'll be at -32x's right?

56. anonymous

right

57. anonymous

everytime i think i get it a new problem comes up and im so lost again

58. anonymous

so if you have -6x's and you take away 36x's you'll be at -42x's

59. anonymous

That's ok. New problems should challenge you. Otherwise you'd just be doing things you already know and you wouldn't learn anything.

60. anonymous

yes your right, im just frustrated if i cant get this how am i supposted to get the next two classes