If a centos 7 administrator needs to review the amount of time since the last system reboot and how many users are logged on, what command can they use?

uptime

Explanation:

uptime command gives information about:

A sample output is like this:

19:03:17 up  9:40,  1 user,  load average: 0,20, 0,28, 0,26

which means:

ιт ιѕ ωнєи ѕσмєσиє ρυтѕ ιи α ¢σ∂є σя ѕσмєтнιиg тнαт вяιиgѕ α νιяυѕ, σя мєѕѕєѕ уσυя gαмє υρ, σя αℓℓσωѕ тнєм тσ ¢нєαт.

αи∂ уєѕ ι нανє вєєи нα¢кє∂ вєfσяє(ιт αιит fυи)

нσρє ι ¢συℓ∂ нєℓρ уσυ.