This inequality will be treated like a standard algebraic equation, and so many algebraic properties and rules apply.
First, distributive property.
8s + 7 > -15s + 12 (because there are two - signs, they cancel out and form a + sign.)
Add 15s to both sides.
23s + 7 > 12
Subtract 7 from both sides.
23s > 5
Divide both sides by 23.
s > 5/23
I hope this answers your question!