Answer
The solution set is $(-\infty, 6)$
Work Step by Step
The idea is to isolate x on one side.
Adding, subtracting or multiplying/dividing with a positive number preserves order (the inequality symbol remains).
Multiplying/dividing with a negative number inverts the order (the inequality symbol changes)
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$ 2x+5\lt 17\qquad $ ... $/-5$
$ 2x\lt 12\qquad $ ... $/\div 2$, (positive)
$ x\lt 6$
The solution set is $(-\infty, 6)$