Răspuns:
[tex]1 + 2 - (3 + 4 \times (5 +6 \div (7 - n))) = 63 \\ \\ 2 - 3 - 4 \times (5 +6 \div (7 - n)) = 63 - 1 \\ \\ - 4 \times (5 + 6 \div (7 - n)) = 63 - 2 + 3 \\ \\ - 4 \times 5 - 4 \times 6 \div (7n - n) = 64 \\ \\ - 20 - 4 \times 6 \div (7 - n) = 64 \\ \\ - 4 \times 6 \div (7 - n) = 64 + 20 \\ \\ - 4 \times 6 \div (7 - n) = 84 \\ \\ - 6 \div (7 - n) = 21 \\ \\ 7 - n = 21 \times ( - 6) \\ \\ 7 - n = - 126 \\ \\ 7 + 126 = n \\ \\ \boxed{n = 133}[/tex]
