Given the inequality:
$$\left|{2 x - 4}\right| < 6$$
To solve this inequality, we must first solve the corresponding equation:
$$\left|{2 x - 4}\right| = 6$$
Solve:
For every modulo expressions in the equation
allow cases, when this expressions ">=0" or "<0",
solve the resulting equation.
1.$$2 x - 4 \geq 0$$
or
$$2 \leq x \wedge x < \infty$$
we get the equation
$$\left(2 x - 4\right) - 6 = 0$$
after simplifying we get
$$2 x - 10 = 0$$
the solution in this interval:
$$x_{1} = 5$$
2.$$2 x - 4 < 0$$
or
$$-\infty < x \wedge x < 2$$
we get the equation
$$\left(4 - 2 x\right) - 6 = 0$$
after simplifying we get
$$- 2 x - 2 = 0$$
the solution in this interval:
$$x_{2} = -1$$
$$x_{1} = 5$$
$$x_{2} = -1$$
$$x_{1} = 5$$
$$x_{2} = -1$$
This roots
$$x_{2} = -1$$
$$x_{1} = 5$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{2}$$
For example, let's take the point
$$x_{0} = x_{2} - \frac{1}{10}$$
=
$$-1 + - \frac{1}{10}$$
=
$$- \frac{11}{10}$$
substitute to the expression
$$\left|{2 x - 4}\right| < 6$$
$$\left|{-4 + \frac{\left(-11\right) 2}{10}}\right| < 6$$
31/5 < 6
but
31/5 > 6
Then
$$x < -1$$
no execute
one of the solutions of our inequality is:
$$x > -1 \wedge x < 5$$
_____
/ \
-------ο-------ο-------
x2 x1