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|-3x-7|>5 inequation

A inequation with variable

The solution

You have entered [src]
|-3*x - 7| > 5
$$\left|{- 3 x - 7}\right| > 5$$
|-3*x - 7| > 5
Detail solution
Given the inequality:
$$\left|{- 3 x - 7}\right| > 5$$
To solve this inequality, we must first solve the corresponding equation:
$$\left|{- 3 x - 7}\right| = 5$$
Solve:
For every modulo expressions in the equation
allow cases, when this expressions ">=0" or "<0",
solve the resulting equation.

1.
$$3 x + 7 \geq 0$$
or
$$- \frac{7}{3} \leq x \wedge x < \infty$$
we get the equation
$$\left(3 x + 7\right) - 5 = 0$$
after simplifying we get
$$3 x + 2 = 0$$
the solution in this interval:
$$x_{1} = - \frac{2}{3}$$

2.
$$3 x + 7 < 0$$
or
$$-\infty < x \wedge x < - \frac{7}{3}$$
we get the equation
$$\left(- 3 x - 7\right) - 5 = 0$$
after simplifying we get
$$- 3 x - 12 = 0$$
the solution in this interval:
$$x_{2} = -4$$


$$x_{1} = - \frac{2}{3}$$
$$x_{2} = -4$$
$$x_{1} = - \frac{2}{3}$$
$$x_{2} = -4$$
This roots
$$x_{2} = -4$$
$$x_{1} = - \frac{2}{3}$$
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
$$x_{0} = x_{2} - \frac{1}{10}$$
=
$$-4 + - \frac{1}{10}$$
=
$$- \frac{41}{10}$$
substitute to the expression
$$\left|{- 3 x - 7}\right| > 5$$
$$\left|{-7 - \frac{\left(-41\right) 3}{10}}\right| > 5$$
53    
-- > 5
10    

one of the solutions of our inequality is:
$$x < -4$$
 _____           _____          
      \         /
-------ο-------ο-------
       x2      x1

Other solutions will get with the changeover to the next point
etc.
The answer:
$$x < -4$$
$$x > - \frac{2}{3}$$
Solving inequality on a graph
Rapid solution [src]
Or(And(-oo < x, x < -4), And(-2/3 < x, x < oo))
$$\left(-\infty < x \wedge x < -4\right) \vee \left(- \frac{2}{3} < x \wedge x < \infty\right)$$
((-oo < x)∧(x < -4))∨((-2/3 < x)∧(x < oo))
Rapid solution 2 [src]
(-oo, -4) U (-2/3, oo)
$$x\ in\ \left(-\infty, -4\right) \cup \left(- \frac{2}{3}, \infty\right)$$
x in Union(Interval.open(-oo, -4), Interval.open(-2/3, oo))