Răspuns
x - ( 642 - 284 ) = 607
x - 358 = 607
x = 607 + 358
x = 965
_________________
x - ( 159 + 266 ) = 340
x - 425 = 340
x = 340 + 425
x = 765
_________________
x + ( 800 - 647 ) = 729
x + 153 = 729
x = 729 - 153
x = 576
____________________
x - ( 654 - 290 ) = 56
x - 364 = 56
x = 56 + 364
x = 420