A1. The number $-\sqrt{5}$ is a solution to the equation:
(A) $\sqrt{x}=-5$
(B) $x^{2}=\sqrt{5}$
(C) $x^{2}+5=0$
(D) $x^{2}=-5$
(E) $x^{2}=5$
A1. The equation $x^{2}=5$ has solutions $x= \pm \sqrt{5}$, therefore the number $-\sqrt{5}$ is a solution to this equation.