Substitute x =-2 and y =- 1 into y = a (x+ 1) 2-2a = 1 above.

Therefore, the analytical formula y = (x+ 1) 2-2.

2 With the highest point of the bridge arch as the origin, the parabolic opening is downward.

The vertex is at the origin, and the analytical formula is y = ax 2.

If the span is 40m and 40/2=20, then x is greater than or equal to -20 and less than or equal to 20.

The maximum height is 16.

Then the lowest parabola y=- 16.

Substitute y =- 16 and x = 20 into y = ax 2.

The answer is a=0.04.

So the analytical formula is y = 0.04 x 2.

3 to this vertex.

The highest point of shot put is 2.5m.

Xiao Ming's shooting height1.6m.

The coordinates are (0, 1.6).

Substitute x=0, y= 1.6 into y=-0. 1(x-k)? +2.5 medium

The solution is k= plus or minus 3 (if you vote right, it is 3, if you vote left, it is -3).

Think of it as 3.

Then substitute y=0 into y=-0. 1(x-3)? +2.5,

(x-3)^2=25

x 1=7，x2=-3

Because people think it is still to the right.

So it should be 7 meters.

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