college algebra
posted by alli .
graph the function and state the vertex axis of symmetry, the intercepts, if any: f(x)=x^28x+15
Please show work so i can understand this. thank you

F(x) = Y = x^2  8x + 15.
h = Xv = B/2A = 8 / 2 = 4.
K = Yv = 4^2  8*4 + 15 = 1.
V(h,k) = V(4,1).
Axis = h = 4.
The intercepts are the value of X when
Y = 0:
Y = x^2  8x + 15 = 0
C = 15 = (1)*(15) = (3)*(5).
We select 3 and 5 for factoring because the sum = B(8).
(x5)(x3) = 0
x5 = 0
X = 5.
x3 = 0
X = 3.
Intercepts(Solution set): X = 5, and 3.
To graph the function, select values of X below and above h; and calculate the
corresponding value of Y.
(x,y). Y = x^2  8x + 15.
(1,8).
(2,3).
(3,0).
V(4,1).
(5,0).
(6,3).
(7,8).