Right after acquiring the constants A and B It really is somewhat basic to compute the integral ##int frac dx x^2 + 9 ## as it may now be composed as two less complicated integrals. I attempted but I are not able to see how ##A,B## are constants? The article https://gabletoppak.com/the-growing-threat-of-marine-pollution-and-how-gabletop-cartons-offer-a-solution/