Question

If R is a relation defined on the set Z of integers by the rule (x, y) ∈ R ⇔ x² + y² = 9, then write domain of R.

Answer 1

We need to find (x, y) ∈ R such that x² + y² = 9.
$$\begin{gathered} \mathrm{Now}, \\ {\left(3\right)}^2+0^2=9 \\ \Rightarrow {\left(-3\right)}^2+0^2=9 \end{gathered}$$
x can take values $-$3, 0 and 3.
∴ Domain (R) = {$-$3, 0, 3}