[ Follow Ups ] [ Post Followup ] [ Main Message Board ] [ FAQ ]

Posted by Soroban on October 11, 2002 at 17:44:23:

: OK, here's the problem. I got one answer, my book got a different answer, and my calculator says both are wrong. Here's the equation:

: 1/8x-1/7x=2, solve for x

: I got:
: 7/56x-8/56x=2
: -1/56x=2

: -56x^-1=2
As Mr. K pointed out, here is the error.
The 56 does not "come up".
(Why did you introduce a negative exponent? We usually avoid them)

: -28x^-1=1
Here's another: the "minus" does not cancel out.

: x=28

: The book got:
: [1/7x-1/8x=2]56
Either the book has a typo, or you typed it incorrectly.
The LCD is 56x.

: 7-8=112x
: -1=112x
: x=-1/112
This is correct!

: My calculator got:
: 1/8x-1/7x=2, x=-112 (using q solver), when I substituted -112 for x, it came out equaling 2
: (1/{8[-112]}-1/{7[-112]}=2).

: I know the calculator is right, and I did find a way to get that answer, and I also see how I got my answer and the book got its answer, but I can't figure out what the book, or I, did wrong.
: P.S. those are one-eighth and one-seventh x.
: :-)

• Yeah Jmiah 17:58:31 10/11/02 (3)

Name:
E-Mail:

Subject: