Codomain

Q. If a function $f:\{1,2,3,4\}\to \{1,2,3,4,5,6,7,8,9\}$ is defined, then the function $f$ can be

1. $f\left(x\right)=2x+1$
2. $f\left(x\right)=|x|$
3. $f\left(x\right)=x^2$
4. $f\left(x\right)=x-1$

Q. Let $A=\{1,2,3\}$ and $B=\{1,4,7,12,15,18\}$. A function $f:A\to B$ is defined by $f\left(x\right)=x^2+3$. Then

1. range of $f$ is $\{4,7,12\}$
2. range of $f$ is $\{1,4,7,12\}$
3. co-domain of $f$ is $\{4,7,12\}$
4. co-domain of $f$ is $\{1,4,7,12,15,18\}$

Q. If $f:\{1,3,4\}\to C$, where $C$ is the co-domain of the function and $f\left(x\right)=x^2-3x+2$, then the co-domain of the function can be

1. Set of first $10$ whole numbers
2. Set of factors of $6$
3. Set of even integers
4. Set of natural numbers

Q. If a function is defined from $A$ to $B$ as


then the total number of elements in domain of function is