Answer:
1,3
Step-by-step explanation:
1,3
Answer: 
<u>Step-by-step explanation:</u>
![12cos\bigg(\dfrac{2\pi}{5}x\bigg)+10=16\\\\\\12cos\bigg(\dfrac{2\pi}{5}x\bigg)=6\\\\\\cos\bigg(\dfrac{2\pi}{5}x\bigg)=\dfrac{1}{2}\\\\\\cos^{-1}\bigg[cos\bigg(\dfrac{2\pi}{5}x\bigg)\bigg]=cos^{-1}\bigg(\dfrac{1}{2}\bigg)](https://tex.z-dn.net/?f=12cos%5Cbigg%28%5Cdfrac%7B2%5Cpi%7D%7B5%7Dx%5Cbigg%29%2B10%3D16%5C%5C%5C%5C%5C%5C12cos%5Cbigg%28%5Cdfrac%7B2%5Cpi%7D%7B5%7Dx%5Cbigg%29%3D6%5C%5C%5C%5C%5C%5Ccos%5Cbigg%28%5Cdfrac%7B2%5Cpi%7D%7B5%7Dx%5Cbigg%29%3D%5Cdfrac%7B1%7D%7B2%7D%5C%5C%5C%5C%5C%5Ccos%5E%7B-1%7D%5Cbigg%5Bcos%5Cbigg%28%5Cdfrac%7B2%5Cpi%7D%7B5%7Dx%5Cbigg%29%5Cbigg%5D%3Dcos%5E%7B-1%7D%5Cbigg%28%5Cdfrac%7B1%7D%7B2%7D%5Cbigg%29)
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<u>Answer</u>
<span>(D) 14.2x0.784
<u>Explanation</u>
We do not have to multiply these number to tell the number of decimal places of the product.
The product of a set of number will have the sum of the decimal places of the factors. For example, in
</span>(A) 5.3478x6.4214 ⇒ 4+4= 8 decimal places
(B) 6.4x3.82 ⇒1+2= 3 decimal places<span>
(C) 521x3.82 </span>⇒ 0+2 = 2 decimal places. <span>
(D) 14.2x0.784</span> = 1+3= 4 decimal places.
the correct answer is (D) 14.2x0.784
