dsolve(diff(y(x),x) = -1/2*x+1+y(x)^2+1/2*x^2*y(x)+a*x*y(x)+1/16*x^4+1/4*a*x^3+1/4*a^2*x^2+y(x)^3+3/4*x^2*y(x)^2+3/2*a*x*y(x)^2+3/16*y(x)*x^4+3/4*y(x)*a*x^3+3/4*a^2*x^2*y(x)+1/64*x^6+3/32*x^5*a+3/16*a^2*x^4+1/8*a^3*x^3,y(x))