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<p>You are trying to prove what using a logic example from a 1973 textbook? This isn’t typically taught in today’s “college algebra” course. I’ve taught college algebra, college algebra and trig, and finite mathematics numerous times. I also took college algebra and pre-calculus as an undergrad. They were basically remediation courses and didn’t involve logic or texts from 1973. One of the courses involved some fairly obscure factoring theorems, but that’s about the extent of the novelty.</p>
<p>ETA: DS has had Geometry, Algebra 2, and Pre-calc, and is now in AP calc, and he says he understands your example just fine.</p>