Răspuns :
d) 542 + x — 117 = 638 => 542 + x = 638 + 117 => 542 + x = 755 => x = 755 — 542 => x = 213 => S = { 213 }
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e) ( 43 + x ) + ( 537 — 214 ) = 975 => 43 + x + 323 = 975 => 43 + x = 975 — 323 => 43 + x = 652 => x = 652 — 43 => x = 609 => S = { 609 }
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e) ( 43 + x ) + ( 537 — 214 ) = 975 => 43 + x + 323 = 975 => 43 + x = 975 — 323 => 43 + x = 652 => x = 652 — 43 => x = 609 => S = { 609 }
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