4(-2r+s)-10,5r

4(-2r+s)-10,5r=-8r+4s-10,5r=4s-18,5r

4(-2r+s)-10,5r = -8r+4s -10,5r= -18,5r+4s Chyba tak ?

4(-2r+s)-10,5r= (8r-4s)-10,5r= 12rs-10,5r=1,5rs PLIS!!!!!!!!