Question

Which of the following quadratics will have a maximum value at x = 3?

(1) y = x² - 6x +19
(3) y=-2x² + 20x - 49
(2) y=-4x² +24x-21
(4) y = 2x² – 3x+7

Answer 1

`\huge\text{Hey there!}`

`\mathsf{y = x^2 - 6x + 19}\\\mathsf{y = 6^2 - 6(3) + 19}\\\mathsf{y = 36 - 18 + 19}\\\mathsf{y = 18 + 19}\\\mathsf{y = 37}`

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`\mathsf{y = -2x^2 + 20x - 49}\\\mathsf{y = -2(3)^2 + 20(3) - 49}\\\mathsf{y = -2(9) + 60 - 49}\\\mathsf{y = -18 + 60 - 49}\\\mathsf{y = 42 - 49}\\\mathsf{y = -7}`

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`\mathsf{y = -4x^2 + 24x - 21}\\\mathsf{y = -4(3)^2 + 24(3) - 21}\\\mathsf{y = -4(9) + 72 - 21}\\\mathsf{y = -36 + 72 - 21}\\\mathsf{y = 36 - 21}\\\mathsf{y = 15}`

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`\mathsf{y = 2x^2 - 3x + 7}\\\mathsf{y = 2(3)^2 - 3(3) + 7}\\\mathsf{y = 2(9) - 9 + 7}\\\mathsf{y = 18 - 9 + 7}\\\mathsf{y = 9 + 7}\\\mathsf{y = 16}`

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`\large\text{Good luck on your assignment \& enjoy your day!}`

~
`\frak{Amphitrite1040:)}`