×-20=40,×+15=45,96-×=30
X-20=40 x=40-20 x=20 x+15=45 x=45-15 x=30 96-x=30 x=96-30 x=66
Х-20=40 х=40+20 х=60 60-20=40 х+15=45 х=45-15 х=30 30+15=45 96-х=30 х=96-30 х=66 96-66=30