Solve: −4x > 30, when

$-4 x>30$

$\Rightarrow x<-\frac{30}{4}$        (Dividing both the sides by $-4$ )

$\Rightarrow x<-\frac{15}{2}$

(i) $x \in R$

Then, the solution of the given inequation is $\left(-\infty,-\frac{15}{2}\right)$.

(ii) $x \in Z$

Then, the solution of the given inequation is $\{\ldots \ldots \ldots-9,-8\}$.

(iii) $x \in N$

Then, the solution of the given inequation is $\phi$.