Respuesta :
To solve the system of equations [tex] \left \{ {{y = x^2-4x-21} \atop { y =-5x-22}} \right. [/tex] you should equate right sides of both equations:
[tex] x^2-4x-21=-5x-22, \\ x^2+x+1=0, \\ D=1^2-4\cdot 1=1-4=-3[/tex].
Since D<0, this equation has no solutions, and system of equations haven't solutions too.
[tex] x^2-4x-21=-5x-22, \\ x^2+x+1=0, \\ D=1^2-4\cdot 1=1-4=-3[/tex].
Since D<0, this equation has no solutions, and system of equations haven't solutions too.