we know that
the equation of a parabola is of the form
y=a*(x-h)²+k--------> is a vertical parabola
(h,k) is the vertex
y=−14x²+4x−19
Factor the leading coefficient
y=-14*(x²-4/14x)-19
y=-14*(x²-2/7x)-19
Complete the square Remember to balance the equation
y=-14*(x²-2/7x+(1/49)-(1/49))-19
y=-14*(x²-2/7x+(1/49))-19+14/49
Rewrite as perfect squaresy=-14*(x-1/7)²-917/49
the vertex of the parabola is
h=(1/7)-----> 0.1429
k=(-917/49)----> -18.7143
the vertex of the parabola is
(0.1429, -18.7143)
see the attached figure