Many One Function

Q.

Which of the relations is not a function?

1. one-one

2. many one

3. domain = codomain

4. one many

Q. The function $f\left(x\right)=\frac{x^2+4x+30}{x^2-8x+18}$ is

1. one-one
2. onto
3. both one-one and onto
4. many one

Q. $f:R\times R\to R$ such that f(x + iy) = $\sqrt{x^2+y^2}$. Then, f is

1. many – one and into
2. one-one and onto
3. many – one and onto
4. one – one and into