（9-x²）分之2x+x-3分之一-x²+6x+9分之-2=2x/(3+x)(3-x)-1/(3-x)+2/(x+3)²=[2x(x+3)-(x+3)²+2(3-x)]/(x+3)²(3-x)=(2x²+6x-x²-6x-9+6-2x)/(x+3)²(3-x)=(x²-2x-3)/(x+3)...