Somebody please help me with this Algebra!!!! Thank You =]?

2008-04-03 7:51 am
I was wondering how to solve this:

25 - x² / 12 ( as a fraction.... ) times 6/ 5 - x ( as a fraction.. )

回答 (5)

2008-04-03 8:16 am
✔ 最佳答案
(5 - x)(5 + x)_____6
---------------- X-----------
12____________(5 - x)


(5 + x)
---------
2
2008-04-03 3:11 pm
= ([25 - x²]/12)(6/[5 - x])
= ([25 - x²]/2)(1/[5 - x])
= (x + 5)/2

Answer: (x + 5)/2

Proof (going back to the multiplicand by dividing the product, (x + 5)/2 with the multiplier, 6/(5 - x).):
= ([x + 5]/2)/(6/[5 - x])
= ([x + 5]/2)([5 - x]/6)
= ([x + 5][5 - x])/(2 * 6)
= (5x - x² + 25 - 5x)/12
= (25 - x²)/12
This insures that our answer is correct.
2008-04-03 6:55 pm
(25 - x^2)/12 * 6/(5 - x)
= (5 + x)(5 - x)/12 * 6/(5 - x)
= (5 + x)/2
2008-04-03 2:57 pm
I suppose you just want to simplify this expression - since it is not an equation, we can't "solve" it

Since (25-x^2) = (5-x)(5+x) We can rewrite this

[(5-x)(5+x)]/12 * 6/(5-x)

So, cancel the factors that match on the top and bottom
By "cancel" I mean replace (5-x)/(5-x) = 1
(notice that 12 = 6 * 2)

So, the (5-x) factors cancel and the 6 s cancel
This leaves

(5+x)/2
2008-04-03 2:56 pm
25 - x^2 6
_______ x ____
12 5-x

Just factor the numerator of the first fraction.

(5-x) (5+x) 6
________ x ____
12 5-x

Simplify..

(5 + x) . 6
_____ ___
12 1

And then simplify again by dividing the 6 and 12 by 6.

5 + x 1
_____ . ___
2 1

5+x
____
2

That's your final answer.


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