I am refreshing my math skills by reading through one of my math books: Mathematik, the second edition.
In Exercise 2.8, one question was if
$\forall (x,z) \in \mathbb{R}^2 \,\, \exists y \in \mathbb{R}:x\cdot y = z $
is a true statement. In the solution, it says it is not.
Can someone give me a counterexample, since I can not come up with one?
Hint: take $x=0$. What can you say about $x \cdot y$?