Na Du La Cu At Evaluate Be sure to check by differentiating 61 7 1 at dt Determine a change of variables from t to u Choose the correct answer below A u 6t 7 B u t C u 6t 7 D u t 7 Write the integral in terms of u S 6t 7 1 dt S du Type an exact answer Use parentheses to clearly denote the argument of each function