Question:
Write the set of values of $x$ satisfying the inequations $5 x+2<3 x+8$ and $\frac{x+2}{x-1}<4$.
Solution:
We have:
$5 x+2<3 x+8$ and $\frac{x+2}{x-1}<4$
$\Rightarrow 2 x<6$ and $\frac{x+2}{x-1}-4<0$
$\Rightarrow x<3$ and $\frac{x+2-4 x+4}{x-1}<0$
$\Rightarrow x \in(-\infty, 3)$ and $\frac{-3 x+6}{x-1}<0$
$\Rightarrow x \in(-\infty, 3)$ and $\frac{-x+2}{x-1}<0$
For $\frac{-x+2}{x-1}<0$, critical points are 1 and $2 .$
$\Rightarrow x \in(2, \infty) \cup(-\infty, 1)$
$\therefore x \in(-\infty, 1) \cup(2,3)$