Given the inequality:
$$\left(\frac{3}{2}\right)^{\frac{\left(x^{2} + x\right) - 20}{x}} \leq \left(\frac{3}{2}\right)^{0}$$
To solve this inequality, we must first solve the corresponding equation:
$$\left(\frac{3}{2}\right)^{\frac{\left(x^{2} + x\right) - 20}{x}} = \left(\frac{3}{2}\right)^{0}$$
Solve:
$$x_{1} = -5$$
$$x_{2} = 4$$
$$x_{1} = -5$$
$$x_{2} = 4$$
This roots
$$x_{1} = -5$$
$$x_{2} = 4$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} \leq x_{1}$$
For example, let's take the point
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$-5 + - \frac{1}{10}$$
=
$$- \frac{51}{10}$$
substitute to the expression
$$\left(\frac{3}{2}\right)^{\frac{\left(x^{2} + x\right) - 20}{x}} \leq \left(\frac{3}{2}\right)^{0}$$
$$\left(\frac{3}{2}\right)^{\frac{-20 + \left(- \frac{51}{10} + \left(- \frac{51}{10}\right)^{2}\right)}{- \frac{51}{10}}} \leq \left(\frac{3}{2}\right)^{0}$$
91 419
--- ---
510 510
2 *3 <= 1
---------
3
one of the solutions of our inequality is:
$$x \leq -5$$
_____ _____
\ /
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x1 x2
Other solutions will get with the changeover to the next point
etc.
The answer:
$$x \leq -5$$
$$x \geq 4$$