Re: Linear Equation - Going Crazy 1 problem

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Posted by Soroban on September 25, 2002 at 01:43:46:

In Reply to: Linear Equation - Going Crazy 1 problem posted by Andrea Lungu on September 23, 2002 at 23:42:25:

: The problem I have is this:

: x _ 4-x
: _______ ________

: 2x - 4 x^2 - 2x

Intresting! The layout was preserved in the "Comments" box.

Even with the poorly-spaced expression in the original post, I guessed
what the problem was supposed to look like.

To add or subtract fractions, you need a common denominator.

You fractions are: x/2(x-2) and (4-x)/x(x-2); the LCD is 2x(x-2).

To make the two denominators equal to the LCD, we must do some work:
multiply the first fraction by x/x, the second by 2x2, and get:
x^2/2x(x-2) - 2(4-x)/2x(x-2)

The denominators are equal, so we simplify the numerator: x^2 - 8 + 2x
and put it over the LCD: (x^2 + 2x - 8)/2x(x - 2)

Ha! The numerator factors, so the fraction is: (x+4)(x-2)/2x(x-2)

The (x-2)s cancel, leaving (x+4)/2x

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