In a ring with identity, prove that (−1) · (−1)= 1.
107390
Why is (-1)(-1) = 1?
110313
Prove that $\gcd(f(x),g(x)) = 1$.
31933
$x^2 = 1$ in the ring $\mathbb{Z}/n \mathbb{Z}$
6012
Prove that $\gcd(a^n - 1, a^m - 1) = a^{\gcd(n, m)} - 1$
87848
Formal proof for $(-1) \times (-1) = 1$
83100
Prove that the center of a ring is a subring.
72507
Does $ab=1$ imply $ba=1$ in a ring?
25004
Proving $\binom{m}{n} + \binom{m}{n-1} = \binom{m+1}{n}$ algebraically
4610
Proving an identity with a combinatorial proof: $\binom{n}{k}\binom{k}{r}=\binom{n}{r}\binom{n-r}{k-r}$
72424
Suppose 1 ≤ k ≤ n − 1 and gcd(k, n) = 1. Prove that gcd(n − k, n) = 1
111515
Proving that $-a=(-1)\cdot a$
111505
Proof $\binom{p-1}{k}\equiv (-1)^k \mod{p}$
29568
Prove that the determinant of $ A^{-1} = \frac{1}{det(A)} $- Linear Algebra
99052
Prove that $( 1 + n^{-2}) ^n \to 1$.
124564
Prove the ring $a+b\sqrt[3]{2}+c\sqrt[3]{4}$ has inverse and is a field
94580
Prove that, $\binom{3n}{r}=\binom{3n-1}{r} + \binom{3n-1}{r-1}$
20878
If $(a,b)=1$ then prove $(a+b, ab)=1$.