Step 1 In this situation, finding the indefinite integral is most easily achieved using the method of integration by substitution. The first step in this method is to let u = g(x), where g(x) is part of the integrand and is usually the "inside function" of a composite function f(g(x)). For the given indefinite integral 6X5 + 8 dx, observe that the integrand involves the composite function ( x6 + 8x) 2 (x6 + 8x) with the "inside function" g(x) = x6 + 8x. Therefore, we will choose u = x6 - Submit Skip (you cannot come back)