Question

Question #018ee

Answer 1

I would say C. III is true.

Explanation:

`f(-x,-y) = (-x)^2+(-x)(-y)+(-y)^2 = x^2-x(-y)+y^2 = x^2+xy+y^2`

Also, `f(-x,y)=x^2-xy+y^2` and `f(x,-y)=x^2-xy+y^2`