−75 Looks Right — But It’s the VALUE, Not the x

Here is the pain point: in final-week SAT practice, students do the math right — they find the roots −2 and 8, even the vertex value −75 — then bubble an intermediate number when the question asked for the vertex’s x-coordinate, and lose a point they earned. A parabola is symmetric: the vertex x is the midpoint of the intercepts, (−2 + 8) ÷ 2 = 3. Or check it in Desmos: graph it and the vertex reads (3, −75) — the question wants the x, 3, not the −75 value. Always re-read what the question actually asked for.

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