Question 522941
{{{ x^2-9 = 2x }}}
{{{ x^2 -2x -9 = 0 }}}
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{{{ graph(500,500,-10,10,-20,20,x^2-2*x-9) }}}
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complete the square
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{{{ x^2 -2x +1 = 9 +1 }}}
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{{{ (x-1)^2 = 10 }}}
{{{ (x-1) = sqrt(10) }}}
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{{{ sqrt(10) = 3.16227766016838 }}}
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Remember the sqrt is plus or minus.
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{{{ x -1 = -3.16227766016838 }}}
{{{ x = -2.16227766016838 }}}
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{{{ x-1 = 3.16227766016838 }}}
{{{ x = 4.16227766016838 }}}
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OR
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You could have used the quadratic equation.
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*[invoke quadratic "x", 1, -2, -9 ]