dsolve(diff(y(x),x)-R1(x,(a4*x^4+a3*x^3+a2*x^2+a1*x+a0)^(1/2))*R2(y(x),(b4*y(x)^4+b3*y(x)^3+b2*y(x)^2+b1*y(x)+b0)^(1/2)) = 0,y(x))