Question 258937
600=350+1.25x
250=1.25x
They are  equivalent. They have all the same solutions.
Simplify the first by subtracting 350 from both sides and it becomes the second.
Since we have only one variable it is a vertical line. where 
x=250/1.25
x=25000/125 
so
 x=200 with slope undefined and y anything you want.  never changes.
It doesn't really have a y=mx+b form 
Since m is undefined and it never cross the y axis.
Standard form is ax+by+c=0 the b's are not the same b's
as in the slope form 
If we were told that y=350+1.25x and y =600
that would be a different line with slope 1.25 and y intercept at (0, 350)