Given the inequality:
$$- \left(\frac{11}{25}\right)^{x - \frac{1}{2}} - 6 \cdot 5^{x} + 6 \cdot 5^{x} + 1 \geq \frac{1}{4}$$
To solve this inequality, we must first solve the corresponding equation:
$$- \left(\frac{11}{25}\right)^{x - \frac{1}{2}} - 6 \cdot 5^{x} + 6 \cdot 5^{x} + 1 = \frac{1}{4}$$
Solve:
Given the equation:
$$- \left(\frac{11}{25}\right)^{x - \frac{1}{2}} - 6 \cdot 5^{x} + 6 \cdot 5^{x} + 1 = \frac{1}{4}$$
or
$$\left(- \left(\frac{11}{25}\right)^{x - \frac{1}{2}} - 6 \cdot 5^{x} + 6 \cdot 5^{x} + 1\right) - \frac{1}{4} = 0$$
or
$$- \frac{5 \sqrt{11} \left(\frac{11}{25}\right)^{x}}{11} = - \frac{3}{4}$$
or
$$\left(\frac{11}{25}\right)^{x} = \frac{3 \sqrt{11}}{20}$$
- this is the simplest exponential equation
Do replacement
$$v = \left(\frac{11}{25}\right)^{x}$$
we get
$$v - \frac{3 \sqrt{11}}{20} = 0$$
or
$$v - \frac{3 \sqrt{11}}{20} = 0$$
Expand brackets in the left part
v - 3*sqrt11/20 = 0
Divide both parts of the equation by (v - 3*sqrt(11)/20)/v
v = 0 / ((v - 3*sqrt(11)/20)/v)
do backward replacement
$$\left(\frac{11}{25}\right)^{x} = v$$
or
$$x = \frac{\log{\left(v \right)}}{\log{\left(\frac{11}{25} \right)}}$$
$$x_{1} = \frac{3 \sqrt{11}}{20}$$
$$x_{1} = \frac{3 \sqrt{11}}{20}$$
This roots
$$x_{1} = \frac{3 \sqrt{11}}{20}$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + \frac{3 \sqrt{11}}{20}$$
=
$$- \frac{1}{10} + \frac{3 \sqrt{11}}{20}$$
substitute to the expression
$$- \left(\frac{11}{25}\right)^{x - \frac{1}{2}} - 6 \cdot 5^{x} + 6 \cdot 5^{x} + 1 \geq \frac{1}{4}$$
$$- 6 \cdot 5^{- \frac{1}{10} + \frac{3 \sqrt{11}}{20}} - \left(\frac{11}{25}\right)^{\left(-1\right) \frac{1}{2} - \left(- \frac{3 \sqrt{11}}{20} + \frac{1}{10}\right)} + 1 + 6 \cdot 5^{- \frac{1}{10} + \frac{3 \sqrt{11}}{20}} \geq \frac{1}{4}$$
____
3 3*\/ 11
- - + --------
5 20 >= 1/4
/11\
1 - |--|
\25/ but
____
3 3*\/ 11
- - + --------
5 20 < 1/4
/11\
1 - |--|
\25/ Then
$$x \leq \frac{3 \sqrt{11}}{20}$$
no execute
the solution of our inequality is:
$$x \geq \frac{3 \sqrt{11}}{20}$$
_____
/
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x_1