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Thread: Finding x & y intercepts (found the y-intercept)

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    Finding x & y intercepts (found the y-intercept)

    I need help please with finding the x-intercept for the following:

    $\displaystyle y = -2x^2 +4$

    I got the y-intercept (0,4) by setting x = 0

    However, when I set y = 0 and attempt to solve I get stuck

    $\displaystyle 0 = -2x^2 + 4$

    What are the next steps for finding the x-intercept? Thanks in advance!
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    $\displaystyle x= \pm \sqrt 2$?
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by lilrhino View Post
    I need help please with finding the x-intercept for the following:

    $\displaystyle y = -2x^2 +4$

    I got the y-intercept (0,4) by setting x = 0

    However, when I set y = 0 and attempt to solve I get stuck

    $\displaystyle 0 = -2x^2 + 4$

    What are the next steps for finding the x-intercept? Thanks in advance!
    $\displaystyle 0 = -2x^2 + 4$ .........subtract 4 from both sides

    $\displaystyle \Rightarrow -4 = -2x^2$ .........Now divide through by -2

    $\displaystyle \Rightarrow 2 = x^2$ .............Now take the squareroot of both sides

    $\displaystyle \Rightarrow \pm \sqrt {2} = x$

    So our x-intercepts are: $\displaystyle \left( \sqrt {2} , 0 \right) \mbox { and } \left( - \sqrt {2} , 0 \right)$
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