Answer
The statement is false when $x=1$ and $y=4$.
Work Step by Step
Written in standard english, the logical statement $\forall$ means "for all". Therefore, the statement we are trying to disprove is "For all real numbers $x$ and $y$, $\sqrt {x+y}=\sqrt{x}+\sqrt y$ " When we plug $1$ in for $x$ and $4$ in for $y$, we get $\sqrt{1+4}=\sqrt{1}+\sqrt{4}\Rightarrow\sqrt{5}=3$, which is false. Therefore, the statement is false when $x=1$ and $y=4$.
