Answer
$10 + 2\sqrt21$
Work Step by Step
Step 1: We will use the formula, $(a+b)^{2}= a^{2} + 2ab + b^{2}$, in this question
Step 2: $(\sqrt 7+\sqrt 3)^{2}$ = $(\sqrt 7)^{2} + 2\sqrt 7\sqrt 3 + (\sqrt 3)^{2} $
Step 3: $7 + 2\sqrt (7\times3) + 3 = 10 + 2\sqrt 21$
Step 4: Therefore, the answer is $10 + 2\sqrt21$
