Let $f: R \rightarrow R$ be defined by $f(x)=x^2+1$. Then,the pre-images of $17$ and $-3$ respectively are

If $f$ is a relation from the set of positive real numbers to the set of positive real numbers defined by $f(x) = 3x^2 - 2$,then $f$ is

Which of the following relations are functions? Give reasons. If it is a function,determine its domain and range.
$\{(2,1), (4,2), (6,3), (8,4), (10,5), (12,6), (14,7)\}$

The function $t$ which maps temperature in degree Celsius into temperature in degree Fahrenheit is defined by $t(C) = \frac{9C}{5} + 32$. Find $t(0)$.

Examine the following relation and state whether it is a function or not,giving reasons:
$R = \{(2, 1), (3, 1), (4, 2)\}$

Let $N$ be the set of natural numbers and the relation $R$ be defined on $N$ such that $R = \{(x, y) : y = 2x, x, y \in N \}$. What is the domain,codomain,and range of $R$? Is this relation a function?