Prove if $x<y$ then $x+z<y+z$
92290
For each $x,y,z∈\mathbb N$, if $x<y$ then $x+z<y+z$
14677
Proving the exponential inequality: $x^y+y^x\gt1$
152495
Prove that if $X$ and $Y$ are Normal and independent random variables, $X+Y$ and $X-Y$ are independent
157733
Are positive real numbers $x,y$ allowed to be taken out during this proof?
89792
Let $x,y$ be positive real numbers. Then $x<y$ iff $x^n<y^n$ for all $n\in \mathbb{N}$
49882
Proving $f(x,y,z)=\big(\frac{x}{a+x+y+z}, \frac{y}{a+x+y+z}, \frac{z}{a+x+y+z} \big)$ is injective
82742
Proving that ${x +y+n- 1 \choose n}= \sum_{k=0}^n{x+n-k-1 \choose n-k}{y+k-1 \choose k} $
71361
Prove that $x^x+y^y=z^z$ doesn't have integer solutions
54380
Prove if $|z| < 1$ and $ |w| < 1$, then $|1-zw^*| \neq 0$ and $| {{z-w} \over {1-zw^*}}| < 1$
96153
$ x^3<y^3 \iff x<y $ proof issue.
152693
If $C|a$ and $C|b$ then $C|(ax+by)$
97667
If $a<b$, $c<d$ then $a+c<b+d$?
31295
$x+y\sqrt{2}$ infimum ($x,y\in \mathbb{Z}$)
2315
How to prove that $\lVert x + y\rVert = \lVert x\rVert + \lVert y \rVert \implies \lVert tx + (1-t)y\rVert = t\lVert x\rVert + (1-t)\lVert y \rVert$?
76267
Prove that: $x_1\cdot x_2\cdots x_n>y_1\cdot y_2\cdots y_m$.
55016
Prove that if ($d(x,y)=0$ iff $x=y$) and if $d(x,z)\leq d(x,y)+d(z,y)$ then $d$ is a metric
151985
If $p$ is a prime and $x,y \in \mathbb{Z}$, then $(x+y)^p \equiv x^p+y^p \pmod{p}$