Question

Which of the following has no solution?
{x | x < 0} and {x | x > 0}
{x | x ≤ 0} and {x | x ≥ 0}
{x | x ≤ 0} or {x | x ≥ 0}

Answer 1

Imput interpretation:
{x | x < 0} and {x | x > 0} <--- find a number that is greater than zero AND ALSO less than zero

{x | x ≤ 0} and {x | x ≥ 0} <--- find a number that is greater or equal to zero AND ALSO less or equal zero

{x | x ≤ 0} or {x | x ≥ 0} find a number that is greater or equal to zero OR less or equal zero

Answer 2

what?

Answer 3

can you find a number that is both less than zero AND also greater than zero??