Hey i've found this one incredibly tough i don't know if it's just me(probably) but i think its hard and can't seem to get anywhere

Suppose f(x,y)= A(x2 + Bx + y2 +Cy). What values A, B, C give f(x,y) a local maximum value of 15 at the point (-2, 1)?

Also find all critical points of

f(x, y)=ex(1-cos y)

and classify these critical points.