Solve the integral below with u-substitution. Hints will appear after 3, 6, and 9 attempts. -8 sec(-7:) tan(-72) da sec2(-7x) Let u = Then du = Then, we substitute in the integral to get (which has 'u' and 'du' in it, not 'x' or 'dx'. ) Now this is a basic integral. Evaluate it to get all possible antiderivatives in terms of 'u': and then the final answer is -8 sec(-7x) tan(-72) da = sec?(-7z) Submit answer APR ? 18 0 CS 4. O X Z