Question

Find the vertex of the quadratic function y = x2 + 12x + 40.

Answer 1

to get x-vertex, use the formula
x = -b/2a
here known the values of a = 1 and b = 12
so, x = -12/(2*1) = -12/2 = -6

now, to get y-vertex just subtitute x=-6 to y(x). it means
y(x=-6) = (-6)^2 + 12(-6) + 40
= 36 - 72 + 40
= 4

so, the vertex is at point (-6, 4)