Respuesta :

[tex]\bf \begin{cases} -x^2-x+19=\boxed{y}\\ x=\boxed{y}+80\\ ----------\\ x=\boxed{-x^2-x+19}+80 \end{cases} \\\\\\ x+x+x^2-19-80=0\implies \begin{array}{lcclll} x^2&+2x&-99&=0\\ &\uparrow &\uparrow \\ &11-9&11\cdot -9 \end{array} \\\\\\ (x+11)(x-9)=0\implies \begin{cases} x+11=0\implies &x=-11\\ x-9=0\implies &x=9 \end{cases}[/tex]