Simplify 3(sqrt{45} – 12sqrt{5} + 16sqrt{20}), leaving your answer in surd form.
-
A.
29(sqrt{5}) -
B.
14(sqrt{15}) -
C.
12(sqrt{15}) -
D.
11(sqrt{15})
Correct Answer: Option A
Explanation
3 (sqrt{45} – 12sqrt{5} + 16sqrt{20})
= 3 x (sqrt{9 times 5} – 12 times sqrt{5} + 16 times sqrt{4 times 5})
= 3 x 3 x (sqrt{5} – 12 times sqrt{5} + 16 times 2 times sqrt{5})
= 9(sqrt{5} – 2 sqrt{5} + 32 sqrt{5})
= 9(sqrt{5} + 32sqrt{5} – 12sqrt{5})
= 29(sqrt{5})