find the gradient of

f(x, y) = 7(x^5)(y^4) − 9(x^3)(y^8)

Please enter your answer as a row vector, using the list syntax.

Now what i have done is below which i dont think is right for the question of row vector. Could someone help?

(35*x^4*y^4 - 27*x^2*y^8)i + (28*x^5*y^3 - 72*x^3*y^7)j