Question: Problem to simplify an expression

Dear Users!

Hope everyone is fine. I am want use the command of isolate only red color term. Then I need help to simplify the expression term by term like simplify the rational expressions, combine powers, simplify radicals etc..

x*c*(diff(f(eta), eta))*epsilon/(-epsilon*t+1)^2+(1/2)*x*c^2*(diff(f(eta), eta, eta))*y*epsilon/((-epsilon*t+1)^3*sqrt(c/(nu*(-epsilon*t+1)))*nu)+x*c^2*(diff(f(eta), eta))^2/(-epsilon*t+1)^2-sqrt(c*nu/(-epsilon*t+1))*f(eta)*x*c*(diff(f(eta), eta, eta))*sqrt(c/(nu*(-epsilon*t+1)))/(-epsilon*t+1) = a*x*epsilon/(-epsilon*t+1)^2+a^2*x/(-epsilon*t+1)^2+x*c^2*(diff(f(eta), eta, eta, eta))/(-epsilon*t+1)^2+sqrt(2)*GAMMA*x^2*c^3*(diff(f(eta), eta, eta))*sqrt(c/(nu*(-epsilon*t+1)))*(diff(f(eta), eta, eta, eta))/(-epsilon*t+1)^3+A*g*beta[T]*theta(eta)*T[w]-A*g*beta[T]*theta(eta)*T[infinity]+A*g*beta[C]*phi(eta)*C[w]-A*g*beta[C]*phi(eta)*C[infinity]-sigma*B^2*x*c*(diff(f(eta), eta))/(rho*(-epsilon*t+1))+sigma*B^2*a*x/(rho*(-epsilon*t+1))

I am waiting your postive answer on it.