int(x^(2))/(x^(2)+6x-3)dx

int(x^(2))/(x^(2)+6x-12)dx

int(x^(2))/(x^(2)+6x+12)dx

int(x^(2))/(x^(6)+2x^(3)-3)dx=

int (x^(2))/(x^(6)+2x^(3)+2)dx=

int(x+2)/(2x^(2)+6x+5)*dx

If int(x+2)/(2x^(2)+6x+5)dx =P int(4x+6)/(2x^(2)+6x+5)dx+(1)/(2) int (dx)/(2x^(2)+6x+5') Then the value of P is

int(x^(2))/(x^(6)+x^(3)-2)dx

int (x^(2)dx)/(x^(2)+6x+12)

(3) int(x^(2)-5x+6)/(x-3)dx