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Parabola Vertex problem?
Ive been out of school for about 2 years and am getting back into it and looking for some refreshers and am working through some quizzes and got stuck on a parabola question. Given that f(x) = -3x^2 -1 8x - 15, how do i find the vertex? Thanks!
2 Answers
- Julius NLv 71 decade agoFavorite Answer
Dee had the right idea, but 27 - 15 = +12 not -12
---->-3x^2 -1 8x - 15
-3x^2-18x-15 = -3x²-18x-15
f(x) = -3(x²-2(-3 x) + 9 ) 27 -15 = -3(x-(-3 ))² + 12
vertex=(-3, 12) is maximum
- Dee WLv 71 decade ago
f(x) = -3(x^2 + 6x) - 15
f(x) = -3(x^2 + 6x + 9) - 15 + 3(9)
f(x) = -3(x + 3)^2 - 12
vertex = (-3, -12)
