Question 1100324
This is y=-(2/9)(x^2-6x)
or y=-(2/9)x+(12/9)x
the x value for the vertex (highest point) is -b/2a or -(12/9)/-(4/9), which is 3 feet. y(3)=-(2/9)(-9)=2 feet ANSWER 
The vertex is symmetrical, so if the starting point is 0 feet, the ending point is 6 feet. ANSWER
OR y=(-2/9)(x)(x-6)=0
x=0 and 6.
{{{graph(300,300,-10,10,-5,5,-(2/9)(x^2-6x))}}}