Discover Questions

Prove that for all n>=9 that there exist natural numbers x,y s.t. n=2x+5y.? HOW DO I SOLVED EQUATION 5.9 =6.1 + log ((0.177-X)/X)? Does this integral converge or diverge? integrate (sin^2)/sqrt(x) dx from 0 to pi
I think I should use comparison test but not sure to what? Are aliens evil? What's does E mean in math?