WEBVTT
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At which value of π¦ does the graph of π¦ equals three π₯ squared plus two π₯ plus seven cross the π¦-axis?
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To answer this question, we begin by recalling that we can use an equation to represent the π¦-axis.
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Itβs the vertical line with the equation π₯ equals zero.
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And so, to find the values of π¦ for which the graph of π¦ equals three π₯ squared plus two π₯ plus seven crosses the π¦-axis, weβre going to set each instance of π₯ equal to zero and solve for π¦.
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By setting π₯ equal to zero, we get π¦ equals three times zero squared plus two times zero plus seven.
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Three times zero squared is zero.
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Two times zero is also zero.
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So, we have π¦ is equal to seven.
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And so, we find there is actually only one value of π¦ for which the graph of π¦ equals three π₯ squared plus two π₯ plus seven crosses the π¦-axis.
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Itβs seven.