For f(x) = x^ + 8x - 14, give the axis of symmetry, and the coordinates of the vertex.

X^2 +8x -14 = 0
a = 1
b = 8
c = -14
Vertex x-value = -b / (2*a)
Vertex x-value = -8 / (2*1)
Vertex x-value = -4 which also equals the axis of symmetry

To get the vertex "y"-value we put "-4" into this formula:
vertex y-value = a * (-4)^2 + (b * -4) + c
vertex y-value = 1 * 16 + (-32) -14
vertex y-value = -30

Source:
http://www.1728.org/quadr3.htm

Ifound this on google “that means that the graph of a function with direct variation has these features: it is a straight line: because the slope is the ratio y/x = k. it passes through the origin (0,0): because y = kx = k (0) = 0.” i hope this you for what your looking for