Tuesday, December 23, 2014

Add -5/(x-1)+(2-x)/x

In order to add fractions, they must have common
denominators.  The common denominator in this case is the product of the two given
denominators.  Therefore, the common denominator is x(x -
1).


Multiply the first fraction by
x.


-5 / (x - 1) = -5x / x(x -
1)


Multiply the second fraction by (x -
1)


(2 - x)(x - 1) / x(x -
1)


Now that the fractions have common denominators, you are
able to add their numerators.


numerator:  -5x + (2 - x)(x -
1)


denominator:  x(x -
1)


Multiply the binomials in the numerator using
FOIL.


-5x + 2x - 2 - x^2 +
x


Combine like terms.


-x^2 -
2x - 2


Use the distributive property in the
denominator.


x(x - 1)


x^2 -
x


To avoid negative coefficients, multiply everything by
-1.


numerator:  -1(-x^2 - 2x - 2) = x^2 + 2x +
2


denominator:  -1(x^2 - x) = -x^2 + x = x -
x^2


Simplify the denominator by factoring out the
x.


x - x^2 = x(1 - x)


So now
you have this:


numerator:  x^2 + 2x +
2


denominator:  x(1 -
x)


Simplified answer:  (x^2 + 2x + 2) / [x(1
- x)]

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