7. [-/1 Points] DETAILS BERRAPCALC7 5.6.033. MY NO Find the indefinite integral by the substitution method or state that it cannot be found by our substitution formulas. (If it cannot be found by substitution, enter IMPOSS Use C for the constant of integration. Remember to use absolute values where appropriate.) x + x 4 dx 5x6+ 6x5 8. [-/1 Points] DETAILS BERRAPCALC7 5.6.067. MY NOT The population of a city is expected to be P(x) = x(x + 16) 1/2 million people after x years. Find the average population between year x = 0 and year x = 3. million