1. The problem is to solve an integral or equation using the method of change of variable (substitution). 2. Identify the integral or equation to solve. For example, consider the integral $$\int f(g(x)) g'(x) \, dx$$. 3. Choose a substitution: let $$u = g(x)$$. 4. Then, compute $$du = g'(x) \, dx$$. 5. Rewrite the integral in terms of $$u$$: $$\int f(u) \, du$$. 6. Solve the integral in $$u$$. 7. Substitute back $$u = g(x)$$ to get the solution in terms of $$x$$. This method simplifies integrals by transforming them into a simpler form using substitution. Final answer depends on the specific integral or equation given.