1. The problem statement, all variables and given/known data Verify by substitution that each given function is a solution of the given differential equation. Throughout these problems, primes denote derivatives with respect to x. y'=3x2; y=x3+7 2. Relevant equations 3. The attempt at a solution Well obviously I see that the derivative of y=x3+7 is just 3x2, but what does it mean by verifying by substitution?