56-x=33 X+20=45 X-7=8 9+x=17
56-x=33 x= 23 x+20=45 x= 25 x-7=8 x= 15 9+x=17 x=8
56 - х = 33 х = 56 - 33 х = 23 х + 20 = 45 х = 45 - 20 х = 25 х - 7 = 8 х = 8 + 7 х = 15 9 + х = 17 х = 17 - 9 х = 8