If f(x,y)=x2+3yf(x, y) = x^2 + 3yf(x,y)=x2+3y, what is ∂f∂x\frac{\partial f}{\partial x}∂x∂f?
2x+32x + 32x+3
2x2x2x
333
2x+3y2x + 3y2x+3y