Question

for which values of A the system has no solution$x \leqslant 5 \\ x \geqslant a$

Answer 1

We have that x is euqal or larger than 5.

The system will not have a solution if we demand that x is equal or bigger than a number bigger than 5 (it can not be less and more than 5 at the same time).

Then, the values of a that make the system have no solution are defined by:

$a>5$