Use a change of variables to evaluate the following indefinite integral. ((VX +8)5 dx 21x Determine a change of variables from x to u. Choose the correct answer below. OA. U= (VX +8)5 OB. U= 1 21X Oc. u= 1x +8 OD. U= 1X Write the integral in terms of u. ( vx +8) 5 21X dx = Evaluate the integral. ( (Vx +8) 5 dx = 21x