Question 107261
(-12)/(x^2+ x- 12) + (x^2)/(x+ 4)(x - 3) + (x)/
(x^2 + x – 12)

the {{{x^2+x-12}}} facroises to (x+4)(x-3)

our question becomes

{{{-12/((x+4)(x-3))+x^2/((x+4)(x-3))+x/((x+4)(x-3))}}}

All fractions have the same denominator so we add the numerators

we have 
{{{(-12+x^2+x)/((x+4)(x-3))}}}

-12+x^2+x = x^2+x-12 which factorises to (x+4)(x-3) again

we have 
{{{((x+4)(x-3))/((x+4)(x-3))}}}

=1