Question 262255
There is no "need" to isolate y.
Some people find it convenient.
but just let x=0 and solve for y

 x-5y=5
0-5y=5
y=-1
(0,-1)
and let y=0 and solve for x

 x-5y=5
y=0
x=5
(5,0)
Plot those two points
and connect with a straight line