$$\left. \begin{array} { l } { y = 10 x ^ { 2 } + 5 ; \quad y = - 6 x ^ { 2 } + 8 } \end{array} \right.$$
$x=-\frac{\sqrt{3}}{4}\approx -0.433012702\text{, }y=\frac{55}{8}=6.875$
$x=\frac{\sqrt{3}}{4}\approx 0.433012702\text{, }y=\frac{55}{8}=6.875$
