Given the inequality:
$$3^{2 x - 1} + 3^{2 x - 2} - 3^{2 x - 4} \leq 315$$
To solve this inequality, we must first solve the corresponding equation:
$$3^{2 x - 1} + 3^{2 x - 2} - 3^{2 x - 4} = 315$$
Solve:
$$x_{1} = 3$$
$$x_{2} = \frac{\log{\left(27 \right)} + i \pi}{\log{\left(3 \right)}}$$
Exclude the complex solutions:
$$x_{1} = 3$$
This roots
$$x_{1} = 3$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + 3$$
=
$$\frac{29}{10}$$
substitute to the expression
$$3^{2 x - 1} + 3^{2 x - 2} - 3^{2 x - 4} \leq 315$$
$$- 3^{\left(-1\right) 4 + 2 \cdot \frac{29}{10}} + 3^{\left(-1\right) 2 + 2 \cdot \frac{29}{10}} + 3^{\left(-1\right) 1 + 2 \cdot \frac{29}{10}} \leq 315$$
4/5
105*3 <= 315
the solution of our inequality is:
$$x \leq 3$$
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