\(y=-5x^2-6x+10 <=> y'=-10x-6, y'=0 <=> x=-0.6\)
\(y= -5(-0.6)^2-6(-0.6)+10=11.8\)
so \((x,y)=(-0.6,11.8)\)
\(x^2+18x+5 = 1(x+9)^2+(-76)\)
