solve 2 variable function in terms of one

Hello, I have the function F = 100 - x - 7/(2*x^(3/10)) - y/2 , with x y variables and I would like to solve F=0 and express x in terms of y. As an end result I want to have x=A*y so I can substiture x in another expression. with a simpler function I achieved that by x=solve(F,x) but now that doesnt seem to work. What method should I use to solve that?