Question 723733
{{{y=x2+2x-3}}} --> {{{y=x2+2x+1-4}}} --> {{{y=(x+1)^2-4}}}
{{{(x+1)^2>=0}}} --> {{{(x+1)^2-4>=-4}}}
So for {{{highlight(c<-4)}}} {{{y=x2+2x-3>=-4>c}}}
and the two equations have no point in common.