Since we know the two x-intercepts of the graph of f, it is easier to start with the factored form of a quadratic function.The two x-intercepts are (−2,0) and (8,0) so the equation of f can be written as y=a(x+2)(x−8), in which a is a constant. Since the x-coordinate of the vertex is the average of the two x-intercepts, x=2−2+8​=3 is the x-coordinate of the vertex. The y - coordinate of the vertex is the minimum value of f, which is −225​. In the equation y=a(x+2)(x−8), substitute x=3 and y=−225​ to find the value of a. −225​=a(3+2)(3−8) gives a=21​. So the equation of f is y=21​(x+2)(x−8). To find the y-intercept of the graph of f, substitute 0 for x⋅y=21​(0+2)(0−8)=−8.Therefore, the y-intercept is (0,−8).