Step-by-step explanation:
the function is
x² - 10x + 9
the x value for the axis of symmetry of a quadratic equation is
ax² + bx + c
x = -b/(2a)
in our case
a = 1
b = -10
x = - -10/2 = 10/2 = 5
x=5 is the axis of symmetry.
for the vertex we need also the y :
y = 5² - 10×5 + 9 = 25 - 50 + 9 = -16
the vertex is
(5, -16)
