Step 2. Make the change of variables u = u(x) (where u(x) is the function you selected in question 1) and rewrite the indefinite integral | 2x V4 + x* dx as an indefinite integral in the independent variable u (your new indefinite integral should no longer contain x or dx). Select the resulting integral from the options below. O a. | Vũ du O b. / V4 + u° du O C. | 2x vā du d.