A function f is homogeneous of degree n when f(tx, ty) = tⁿf(x, y). In Exercises 39– 42,

(a) Show that the function is homogeneous and determine n, and

(b) Show that xf_x(x, y) + yf_y(x, y) = nf(x, y).

f(x, y) = 2x² - 5xy