solve the round ones..
put y=0, so you will get f(x)=f(0).
So this means f(x) is a constant function.
it will be option d.
If a function is symmetric about x=a line then,
You can visualise this by any graph as well
For question 8.
You just have to guess the answer by looking to the options.
It will be option C.
Only function that is even and odd respectively is F(x)=constant.
so the answer will be zero.