0,64x=x+0,09

0.64x =  x + 0.09      it makes it easier  if you multiply through by  100....so we have

64x  = 100x  +  9        subtract 100x from both sides

-36x  = 9       divide both sides by -36

x   = -9 / 36   = -1/4

combine like terms.combine 0,064x and x. there is a 1 infront of the x that you can not see so what you will do is add the two you will get 0,065x + 0,09 . just remember that there is a ivisable 1 beforea x that is singular