The given function is f(x) = 2x - 5.
Therefore,
(i) f(0) = 2 x 0 - 5 = 0 - 5 = -5
(ii) f(7) = 2 x 7 - 5 = 14 - 5 = 9
(iii) f(-3) = 2 x (-3) - 5 = - 6 - 5 = -11
Let $R$ be a relation defined on the set $\{1,2,3,4\times\{1,2,3,4\}$ by \[ R=\{((a,b),(c,d)) : 2a+3b=3c+4d\} \] Then the number of elements in $R$ is