1. The problem statement, all variables and given/known data Random example: 2[([x^2] + 3)^7](7x) 2. Relevant equations ? 3. The attempt at a solution I know that somehow you substitute [x^2] + 3 with 'u', but I don't understand the process going forward for it, and my teacher and textbook has some rather convoluted stuff in it, so if someone could explain this concept and how this ends up integrating anything, that would be nice.