Question 102889
4x-5y=0

subtract 4x on both the sides 

4x-4x-5y = 0-4x

-5y = -4x
divide by -5 on both the sides

 -5y/-5  = -4x/-5
 
 y =( 4/5 )x

{{{ graph( 300, 200, -6, 5, -10, 10, (4/5)x) }}}