MathNet 1999 — Part 01 Question 78
Math Olympiad Vault · MathNet 1999 — Part 01
Which of the following statements is true for the set of rational numbers?
For every $x$ there is a $y$ such that for every $z$ there is $x+y+z=x$
for every $x$ there is a $y$ such that for every $z$ there is $x+y+z=z$
for every $x$ there is a $y$ such that for every $z$ there is $x y z=x$
for every $x$ there is a $y$ such that for every $z$ there is $x y z=z$
none of the above statements are correct.