I have read the following formula

limit(x=0 to x=∞)∫e^(-px) dx ( limit (y=x to y=∞) ∫ K(y-x) h(y) dy) =

(limit(u=0 to u=∞)∫K(u) e^pu du)(limit(y=0 to y=∞)∫h(y) e^(-py) dy)

i.e laplace transform application

but the formula doesn't hold true for K(y-x)=e^(-(y-x)) and h(y)=y.

plz reply if someone can help......