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What are the solutions of the equation -x^2+8x+5=0

2 Answers

2 votes


Solution, solve\:for\:x,\:-x^2+8x+5=0\quad :\quad x=-√(21)+4,\:x=4+√(21)


Steps:


-x^2+8x+5=0


\mathrm{Solve\:with\:the\:quadratic\:formula},\\\mathrm{Quadratic\:Equation\:Formula:} \mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}, x_(1,\:2)=(-b\pm √(b^2-4ac))/(2a),\\\mathrm{For\:}\quad a=-1,\:b=8,\:c=5:\quad x_(1,\:2)=(-8\pm √(8^2-4\left(-1\right)5))/(2\left(-1\right)),x=(-8+√(8^2-4\left(-1\right)5))/(2\left(-1\right)):\quad -√(21)+4,\\x=(-8-√(8^2-4\left(-1\right)5))/(2\left(-1\right)):\quad 4+√(21)


\mathrm{The\:final\:solutions\:to\:the\:quadratic\:equation\:are:} x=-√(21)+4,\:x=4+√(21)


\mathrm{Hope\:This\:Helps!!!}


\mathrm{-Austint1414}

User Tom Kadwill
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5.0k points
7 votes

First you get a graphing calculator & enter the equation into y = then hit graph . then hit graph & y= to get the table find where y is 0 and those will be you answers

(-0.583, 0) (8.583, 0)

User Aditya Gupta
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5.4k points