2-5y-(5-2y)=2y-9-(9-4y)
2-5у-(5-2у)=2у-9-(9-4у) 2-5у-5+2у=2у-9-9+4у -5у+2у-2у-4у=-9-9-2+5 -9у=-15 у=-15/-9=5/3
2-5y+(-5+2y)=2y-9-(9-4y) -3y-3=2y-9-(9-4y) -3y-3=2y-9+(-9+4y) -3y-3=6y-18 -9y=3-18 -9y=-15