QuestionFind the second-order partial derivative. Find $f_{x y}$ when $f(x, y)=10 x^{2} y^{4}-7 x^{3} y^{5}$. $160 x y^{3}-21 x^{2} y^{4}$ $80 x y^{3}-21 x^{2} y^{4}$ $80 x y^{3}-105 x^{2} y^{4}$ $160 x y^{3}-105 x^{2} y^{4}$