for the function whose graph is shown below, which is the correct formula for the function. please give me the answer for my daughter

From the graph notice that, the y-intercept is (0,3).
The general form of the line equation with slope m and y -intercept (0,c) is
y=mx+c.
So, here c=3.
The equation will be y=mx+3.
To find slope m use any point on the line.
The point (1,1) is lies on the line.
Substitute x=1, y=1 in y=mx+3.
[tex]\begin{gathered} y=mx+3 \\ 1=m(1)+3 \\ 1-3=m \\ -2=m \end{gathered}[/tex]So, the required formula for the function whose graph is given by figure is
[tex]y=-2x+3[/tex]