y= -8/5x through the point (5,-5)
Parallel lines have the same slope. So the slope of the second line will also be -8/5.
Note that the variable m represents slope of the line.
y= mx+b
y= -8/5x +b the x coordinate is 5
y= -8/5(5) +b the y coordinate is -5
-5= -8 +b
+8=+8 +b
_________
3=b
so the equation of the new line is y=-8/5x+3