Răspuns :
a) 543 + x - 117 = 638
543 + x = 638 + 117
543 + x = 755
x = 755 - 543
x = 212
b ) ( 43 + x ) + (537 - 214 ) =975
(43 + x ) + 323 =975
43 + x =975 - 323
43 + x =652
x = 652 - 43
x = 609
543 + x = 638 + 117
543 + x = 755
x = 755 - 543
x = 212
b ) ( 43 + x ) + (537 - 214 ) =975
(43 + x ) + 323 =975
43 + x =975 - 323
43 + x =652
x = 652 - 43
x = 609