How do you simplify (x^3+x^2-2x)/(x^3+2x^2-x-2)x3+x22xx3+2x2x2?

2 Answers
Mar 15, 2016

(x^3+x^2-2x)/(x^3+2x^2-x-2)=1-1/(x+1)x3+x22xx3+2x2x2=11x+1

with exclusions x != 1x1 and x != -2x2

Explanation:

(x^3+x^2-2x)/(x^3+2x^2-x-2)x3+x22xx3+2x2x2

=(x(x^2+x-2))/(x^2(x+2)-1(x+2))=x(x2+x2)x2(x+2)1(x+2)

=(x(x-1)(x+2))/((x^2-1)(x+2))=x(x1)(x+2)(x21)(x+2)

=(x color(red)(cancel(color(black)((x-1))))color(red)(cancel(color(black)((x+2)))))/(color(red)(cancel(color(black)((x-1))))(x+1)color(red)(cancel(color(black)((x+2)))))

=x/(x+1)

=(x+1-1)/(x+1)

=1-1/(x+1)

with exclusions x != 1 and x != -2

color(white)()
These exclusions are required, because when x=1 or x=-2 both the numerator and denominator of the original rational expression are zero, so the quotient is undefined, but the simplified expression is well behaved at these values of x.

Note however that we do not need to specify x=-1 as an excluded value of our simplification, because it is equally a simple pole of both the original and simplified expressions.

Mar 16, 2016

By factoring and factoring by grouping
(x)/(x+1)

Explanation:

  1. Factor both your numerator and denominator
    (x^3+x^2-2x)/(x^3+2x^2color(red)(-x-2)
    {x(x^2+x-2)}/{(x^3+2x^2)color(red)(-1(x+2)}

  2. Again, factor the remaining terms
    {x(x^2+x-2)}/((x^3+2x^2)-1(x+2))
    {x(x+2)(x-1)}/(x^2(color(blue)(x+2))-1(color(blue)(x+2))
    {x(x+2)(x-1)}/{color(blue)((x+2))(x^2-1)}
    {x(cancel(x+2))cancel((x-1))}/{color(blue)((cancel(x+2))(x+1)(cancel(x-1))}

  3. Final Asnwer:
    (x)/(x+1)