Answer
$2+6i\sqrt {7}$
Work Step by Step
Make the square roots positive by taking out the $i$ and simplify them. then FOIL the two groups of parentheses and combine like terms.
$(-3-\sqrt {-7})^2$
$(-3-\sqrt {-7})(-3-\sqrt {-7})$
$(-3-i\sqrt {7})(-3-i\sqrt {7})$
$9+3i\sqrt {7}+3i\sqrt {7}+(\sqrt {7})^2$
$99+6i\sqrt {7}+(-7)$
$2+6i\sqrt {7}$
