Question:
Solve each of the following system of equations in R.
16. $\frac{7 x-1}{2}<-3, \frac{3 x+8}{5}+11<0$
Solution:
$\frac{7 x-1}{2}<-3$
$\Rightarrow 7 x-1<-6$
$\Rightarrow 7 x<-6+1$
$\Rightarrow x<\frac{-5}{7}$
$\Rightarrow x \in\left(-\infty, \frac{-5}{7}\right) \quad \ldots$ (i)
$\Rightarrow \frac{3 x+8+55}{5}<0$
$\Rightarrow 3 x+63<0$
$\Rightarrow 3 x<-63$
$\Rightarrow x<-21$
$\Rightarrow x \in(-\infty,-21) \quad \ldots$ (ii)
Hence, the solution to the given set of inequations is the intersection of (i) and (ii).
$\left(-\infty, \frac{-5}{7}\right) \cap(-\infty-21)=(-\infty,-21)$
Hence, the solution to the given set of inequations is $(-\infty,-21)$.