∴ Quadratic function y = ax?

Bronx (Bronx)

C can be changed to y=a(x

1)^2-4

(a>0, the opening is upward to have the minimum value)

In addition, the line segment length of the image cut on the X axis is 4.

∴y=0，│x 1-x2│=4=√(x 1

x2)^2-4x 1x2

②

∴a(x

1)^2-4=ax^2

2ax

a-4=0

x 1

x2=-2

x 1x2=(a-4)/a

①

∴ Substitute ① into ② to get a= 1.

The resolution function is y=(x

1)^2-4=x^2

2x-3

Hope to adopt, thank you. .