-13x + 0,5y + 25x - 30y =

25x - 13x - 30y + 0,5y =

12x - 29,5y

[tex]-13x+0,5y+25x-30y = - 13x + 25x + 0,5y - 30y = \boxed{ 12x - 29,5y}[/tex]