If a relation R is defined on the set Z of integers as follows: $(a, b) ∈R⇔a^2 + b^2 = 25$. Then, Domain (R) =

$\{3,4,5\}$ $\{0,3,4,5\}$ $\{0,± 3, ±4, ±5\}$ none of these

$\{0,± 3, ±4, ±5\}$

We have, $(a, b)∈ R⇔a^2+b^2 = 25⇔ b=±\sqrt{25-a^2}$ Clearly, $a = 0 ⇒ b=15, a=±3⇒b=±4$ $a = ± 4 ⇒b = ± 3$ and, $a = ±5⇒b=±0$ Hence, domain (R) = $\{a: (a, b) ∈ R\} = \{0,± 3, ±4, ±5\}$.