Question

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

Answer 1

$Solution, solve\:for\:x,\:-x^2+8x+5=0\quad :\quad x=-\sqrt{21}+4,\:x=4+\sqrt{21}$

$Steps:$

$-x^2+8x+5=0$

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

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

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

$\mathrm{-Austint1414}$

Answer 2

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)