How do you solve 1/(x-1) + 2/(x+3) + (2x+2)/(3-2x-x^2)?

1 Answer
Jul 18, 2016

Maybe you see that the third fraction can be factorized.

Explanation:

3-2x-x^2=-(x^2+2x-3)=-(x-1)(x+3)

Which leaves the whole thing as:
1/(x-1)+2/(x+3)-(2x+2)/((x-1)(x+3)) (mark the - sign)

Next step: make the bottom parts equal:
1/(x-1)xx(x+3)/(x+3)+2/(x+3)xx(x-1)/(x-1)-(2x+2)/((x-1)(x+3))=

(1xx(x+3))/((x-1)(x+3))+(2xx(x-1))/((x-1)(x+3))-(2x+2)/((x-1)(x+3))=

((x+3)+(2x-2)-(2x+2))/((x-1)(x+3))=

Put the numbers and the x's together:
((x+cancel(2x)-cancel(2x))+(3-2-2))/((x-1)(x+3))=((x-1))/((x-1)(x+3))=

Now cancel:
cancel((x-1))/(cancel((x-1))(x+3))=1/(x+3)

NOTE:
Forbidden solutions are x=1and x=-3 as the numerator of the fraction would be =0
graph{1/(x+3) [-16.02, 16.02, -8, 8.02]}