Answer:
A. √9·√16
Explanation:
The square root of a product is the product of the square roots. This is a direct application of the rule lf exponents ...
... (ab)^c = (a^c)(b^c)
Here, a=9, b=16, c=(1/2). (The square root is the same as the 1/2 power.)
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Alternate approach
You can always convert the problem and the answers to numbers to see what matches:
√(9·16) = √144 = 12 . . . . the value of the problem
A. √9·√16 = 3·4 = 12 . . . matches the problem
B. 144 ≠ 12
C. 36 ≠ 12
D. √(9/16) = (√9)/(√16) = 3/4 ≠ 12