Question 1179671
The vertex is at (-h, k), which would be x=3, y=9 or (3, 9)
The axis of symmetry is therefore at x=3.
the y-intercept is where x=0, and that is -2(9)+9=-9 so (0, -9)
The maximum value for this convex upward parabola is when x=3 and that has already been shown to have y=9.
The minimum values are at -oo.
For the zeros, let y=0, 
then -2(x-3)^2=-9
or (x-3)^2=9/2
x-3=+/- 3(sqrt(2)/2
so the zeros are 3+/- (3/2) sqrt (2)
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Can check by writing it in standard form
y=-2x^2+12x-18+9; -2x^2+12x-9=0, or 2x^2-12x+9=0
x= (1/4)(12+/-sqrt(144-72)) or (1/4)(12+/-6 sqrt(2))
roots are 3 +/- (3/2) sqrt(2)
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{{{graph(300,300,-10,10,-10,12,-2(x-3)^2+9)}}}