Răspuns:
a + b = 17
a - b = 5
a * b = ?
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a - b = 5 => a = b + 5
a + b = 17 => b + 5 + b = 17 => 2b + 5 = 17 => 2b = 12 => b = 6
a + b = 17 => a + 6 = 17 => a = 11
a * b = ? => 11 * 6 = 66
