Precalculus: Mathematics for Calculus, 7th Edition

$0+7i$
$\sqrt{-49}$ Rewrite this expression as $(\sqrt{-1})(\sqrt{49})$: $\sqrt{-49}=(\sqrt{-1})(\sqrt{49})=...$ Evaluate $\sqrt{49}$: $...=7\sqrt{-1}=...$ Since $\sqrt{-1}=i$, this expression becomes: $...=7i=...$ Rewrite in $a+bi$ form: $...=0+7i$