The general form is ax+by=c, let's first what we have to create the line in point-slope form, which is:
y-y1=m(x-x1), m=slope and (x1,y1) is any point on the line.
We are given m=-1/5 and (xy)=(0,5) so
y-5=(-1/5)(x-0)
y-5=-x/5 mutiply both sides by 5
5y-25=-x add x to both sides
x+5y-25=0 add 25 to both sides
x+5y=25