Find the maximum of a polynomial trendline

[jondavis1987]

I would like a formula that automatically figures out what the maximum of poynomial trendline will be no matter what numbers i plug in there. I've seen a few explanations but they are all way above my head.

My X axis is A1:A4. Y axis B1:B4

X Axis Y Axis[TABLE="width: 960"]
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[TD="align: right"]9.7[/TD]
[TD="align: right"]105.8[/TD]
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[TD="align: right"]11.9[/TD]
[TD="align: right"]111.5[/TD]
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[TD="align: right"]14.5[/TD]
[TD="align: right"]113.3[/TD]
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[/TR]
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[TD="align: right"]16.8[/TD]
[TD="align: right"]110.2[/TD]
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[/TR]
</tbody>[/TABLE]