Question

simplify the number using the imaginary unit i: (square root) -28 options: a. 2(square root) -7 b. -2(square root) -7 c. i(square root) 28 d. 2i(square root) 28

Answer 1

$\sqrt{-28}=\sqrt{-4\cdot7}=\sqrt{-4}\cdot\sqrt7=2i\sqrt7$

$\sqrt{-28}=\sqrt{4\cdot(-7)}=\sqrt4\cdot\sqrt{-7}=\boxed{2\sqrt{-7}}\to\fbox{a.}$