Question 906423
ve it to a better place:

    A quadratic function is given.
    f(x) =-x^2+18x
    (a) Express the quadratic function in standard form.
    f(x) =-x^2+18x
    (b) Find its vertex and its x- and y-intercept(s).
y=-x^2+18x
complete the square:
y=-(x^2-18+81)+81
y=-(x-9)^2+81
vertex:(9,81)
..
x-intercepts
set y=0
-x^2+18x=0
-x(x-18)=0
x=0
and
x=18
..
y-intercept
set x=0
y=x^2+18x
y=0