Correct Answer: C

Rationale: Rationale: - The imaginary unit, denoted as "i," is defined as the square root of -1. - Therefore, 5i can be expressed as 5 times the square root of -1, which is equivalent to 5√-1. - Option A, -5, is a real number and not an imaginary unit multiple. - Option B, i^5, is equal to i because i raised to any power that is a multiple of 4 results in 1, and i^5 is equivalent to i. - Option D, 1/5i, is the reciprocal of 5i and not equivalent to 5i.

Correct Answer: B

Rationale: There are 1,000 milliliters in a liter. To convert milliliters to liters, you divide by 1,000. Therefore, 8,000 milliliters · 1,000 = 8 liters. This makes option B the correct answer. Option A, 0.8 liters, is incorrect as it is 1/10th of the correct answer. Option C, 0.8 liters (repeated), is also incorrect. Option D, 0.08 liters, is incorrect as it is 1/100th of the correct answer.

Correct Answer: A

Rationale: To determine the largest fraction, it's helpful to convert them to decimals for easier comparison. Converting the fractions to decimals gives: 3/8 = 0.375, 3/9 = 0.333, 3/6 = 0.5, and 3/7 ≈ 0.429. Therefore, 3/7 is the largest fraction among the given options. Choice B, 3/6, is actually equivalent to 3/6 = 0.5 which is greater than 3/7. Choices C and D are smaller fractions compared to 3/7, making them incorrect.

Correct Answer: A

Rationale: When adding two negative numbers, you add their absolute values and keep the negative sign. In this case, -5 + (-8) is equal to -13 because the absolute values of 5 and 8 add up to 13, and the negative sign is retained. Choice B (8) is incorrect because adding two negative numbers results in a negative sum. Choice C (13) is incorrect as it doesn't consider the negative signs of the numbers being added. Choice D (-5) is incorrect because it does not account for the addition of the two negative numbers.

Correct Answer: C

Rationale: The correct answer is C: 5,000 grams. There are 1,000 grams in a kilogram. Therefore, to convert kilograms to grams, you need to multiply the number of kilograms by 1,000. In this case, 5 kilograms is equal to 5 1,000 = 5,000 grams. Choices A and D are incorrect as they incorrectly multiply by 10,000 instead of 1,000. Choice B is incorrect as it divides instead of multiplies, leading to an incorrect conversion.