fcassola fcassola

10-06-2016
Mathematics

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when solving the equation x2-8x-7=0 by completing the square

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nobillionaireNobley nobillionaireNobley

12-06-2016

[tex] x^{2} -8x=7 \\ x^{2} -8x+(-4)^{2} = 7 + (-4)^{2} \\ x^{2} -8x+16 = 7 + 16 \\ (x-4)^{2} =23 \\ x-4= \sqrt{23} \\ x-4= \pm 4.8 \\ x= \pm 4.8+4[/tex]
x = 4.8 + 4 or -4.8 + 4
x = 8.8 or -0.8

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