Answer
a) $3\sqrt 5$
b) $±10$
c) Part (a) adds the radicals, while part (b) multiplies the radicals.
Work Step by Step
a)
$2\sqrt 5 + \sqrt 5$
$\sqrt 5*(2+1)$
$\sqrt 5*(3)$
$3\sqrt 5$
b)
$2\sqrt 5 * \sqrt 5$
$2*\sqrt 5*\sqrt 5$
$2*\sqrt {5*5}$
$2*\sqrt {25}$
$2*±5$
$±10$
