Solve each of the following in equations and represent the solution set on the number line.
$\frac{5 x+8}{4-x}<2, x \in R$
Given:
$\frac{5 x+8}{4-x}<2, x \in R$
Subtracting both the sides by 2
$\frac{5 x+8}{4-x}-2<2-2$
$\frac{5 x+8-2(4-x)}{4-x}<0$
$\frac{5 x+8-8+2 x}{4-x}<0$
$\frac{7 x}{4-x}<0$
Now dividing both the sides by 7
$\frac{7 x}{7(4-x)}<\frac{0}{7}$
$\frac{x}{4-x}<0$
Signs of x:
$x=0$
$x<0$
$x>0$
Signs of 4 – x:
$4-x=0 \rightarrow x=4$
(Subtracting 4 from both the sides, then dividing by -1 on both the sides)
$4-x<0 \rightarrow x>4$
(Subtracting 4 from both the sides, then multiplying by -1 on both the sides)
$4-x>0 \rightarrow x<4$
(Subtracting 4 from both the sides, then multiplying by -1 on both the sides)
At $x=4, \frac{x}{4-x}$ is not defined
Intervals satisfying the condition: < 0
x < 0 or x > 4
Therefore,
$x \in(-\infty, 0) \cup(4, \infty)$