<s>[INST] Finding $\sqrt{(14+6\sqrt 5)^3}+\sqrt{(14-6\sqrt 5)^3}$ Find $$\sqrt{(14+6\sqrt{5})^3}+ \sqrt{(14-6\sqrt{5})^3}$$
A.$72$ 
B.$144$ 
C.$64\sqrt{5}$ 
D.$32\sqrt{5}$
How to cancel out the square root?
 [/INST] Note that $$14\pm 6\sqrt{5}=14\pm 2\sqrt{45}=9+5\pm 2\sqrt{9\times 5}=(\sqrt{9}\pm\sqrt{5})^2$$
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