I have an improper multiple integral that looks like this
$\int_{x} f(x) \int_{y} g(y) dy dx$
I have tried to solve the internal one ($g(y)$) and I reached to this equation
$\int_{x}f(x)\left[constant + constant\int_{y}g(y)dy\right]dx$
I am not sure how to continue solving this integral. Is it possible to write it as
$\int_{x}f(x)*(constant) dx + constant \int_{x}f(x)\int_{y}g(y)dydx$
I appreciate a hint to a method or theory that helps me solve this.