What are the solutions of -x^2+4x=x-4 -5 and o -5 and -1 -1 and 4 0 and 4

Rearrange the equality<br />$-{x}^{2}-x+4=0$ <br />Determine the coefficients $a, b, c$ <br />$a=-1,b=-1,c=4$ <br />Find the discriminant <br />$\Delta = b^2 - 4ac = {(-1)}^{2}-4\times (-1)\times 4 = 17$ <br />Find roots of qudratic equation<br />$\displaystyle \begin{align}&x=\frac{-b\pm \sqrt{b^2-4ac} }{2a}\\&=\frac{-(-1) \pm \sqrt{{{(-1)}^{2}-4\times (-1)\times 4}}}{2\times (-1)}\\&=\frac{-(-1) \pm \sqrt{17}}{2\times (-1)}\\&=\frac{1 \pm \sqrt{17}}{-2}\end{align}$ <br />Calculate<br />$\displaystyle x_{1}=0.5-\frac{1}{2}\sqrt{17},x_{2}=0.5+\frac{1}{2}\sqrt{17}$ <br />