Tìm $n \in \mathbb{Z}$

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1. Tính $n \in \mathbb{Z}$:
a) $2n + 7 = n + 1$
b) $2n + 3 = 3n - 1$
c) $n^2 - 4n + 5 = 0$
d) $n^2 + 2n + 6 = n + 4$
e) $n^3 - 2n^2 - 3n = n^2 + 1$
f) $n^2 + 2n + 10 = 13$
g) $n^2 + n + 2 = n^2 + 2n + 1$
h) $4n^3 - 3n^2 - 2n + 1 = n^4 - 1$
i) $3^n - 1 = 8$
j) $\frac{n^5 - n^3 + n}{120} - \frac{n}{24} + \frac{n}{20} = 0$