notice that the derivative of ln (2x3-7) is equal to 1/(2x3-7) * 6x2 = 6x2/(2x3-7)
Therefore the integral of x2/(2x3-7)
= 1/6 * the integral of 6x2/(2x3-7)
= 1/6 * ln (2x3-7) + C, because the integral of the first derivative of a function is equal to the function plus the constant