Answer :
We are asked to determine the equation of a line that passes through (9,4) and has slope 0. To that let's remember the general equation for a line:
[tex]y=mx+b[/tex]Where "m" is the slope and "b" the y-intercept. Since m = 0, replacing in the equation we get:
[tex]\begin{gathered} y=(0)x+b \\ y=b \end{gathered}[/tex]Now we replace the point (x,y) = (9,4)
[tex]4=b[/tex]Replacing the value of "b = 4":
[tex]y=4[/tex]And thus we get the equation of the line.