The equation of a line can be written as

y−y1=m(x−x1)

where (x1,y1) is either point that lies upon that line. Let us find the slope, this will become our m.

m=(y2−y1)/(x2−x1)

Plugging in our two points gets us to:

m=(5−5)/(2−0) ⟹ m=0

When we have a slope of 0, it indicates that our line is horizontal. Thus the equation of the line can simply be:

y=y0, and in this case both of our points have a y-coordinate of 5. Thus, our equation is:

y=5

y−y1=m(x−x1)

where (x1,y1) is either point that lies upon that line. Let us find the slope, this will become our m.

m=(y2−y1)/(x2−x1)

Plugging in our two points gets us to:

m=(5−5)/(2−0) ⟹ m=0

When we have a slope of 0, it indicates that our line is horizontal. Thus the equation of the line can simply be:

y=y0, and in this case both of our points have a y-coordinate of 5. Thus, our equation is:

y=5