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\begin{array}{cl}-2 x-1 \geq 5 & \\ -2 x \geq 6 & \text { Multiply by }-\frac{1}{2} \\ \left(-\frac{1}{2}\right)(-2 x) \geq(6)\left(-\frac{1}{2}\right) & \text { Reverse the inequality. } \\ x \leq-3 & \end{array}