Prove that $(-a)b = -ab$
11573
Rings and some of their properties
126018
Show that $ e^{A+B}=e^A e^B$
110944
Proving that $AB-BA=cI$ for nontrivial $c \in \mathbb{C}$
13026
Prove that if AB=I_m, then rk(A)=rk(B).
127293
Prove that $(a-b) \mid (a^n-b^n)$
70827
Prove that $\sum_{i = n - b}^{a - m} {a - i \choose m}{b + i \choose n} = {a + b + 1 \choose m + n + 1}$
143979
How can I prove that $|A| + |B| = |A\cup B| + |A\cap B|$?
111003
Prove that if $A\triangle B = C\triangle B$, then $A = C$
120867
How prove this two symmetric matrices $AB=0$
35897
Proof of: $AB=0 \Rightarrow Rank(A)+Rank(B) \leq n$
21737
If $A|B$ and $B|A$ then prove $A=\pm B$
31196
Prove $\binom{n}{a}\binom{n-a}{b-a} = \binom{n}{b}\binom{b}{a}$
64108
how to prove $a+b-ab \le 1$ if $a,b \in [0,1]$?
68705
Prove that $A\ge0, B\ge0$ and $A\ge B$ implies $B^{-1}\ge A^{-1}$
81794
Prove that $(ab,cd)=(a,c)(b,d)\left(\frac{a}{(a,c)},\frac{d}{(b,d)}\right)\left(\frac{c}{(a,c)},\frac{b}{(b,d)}\right)$
33030
Proof that $\inf A = -\sup(-A)$
46286
Prove if $a\mid b$ and $b\mid a$, then $|a|=|b|$ , $a, b$ are integers.