Correct Answer: A

Rationale: To solve the division problem, we need to remember the rule 'Dividing by a fraction is the same as multiplying by its reciprocal.' Therefore, 39 · 8 · 7/6 is equivalent to 39 · 8 6/7. Simplifying this gives (39 6) · (8 7) = 234 · 56 = 56/39. Therefore, the correct answer is A. Choices B, C, and D are incorrect as they do not correctly simplify the given division problem.

Correct Answer: C

Rationale: To convert milliliters to liters, you need to divide by 1000 since there are 1000 milliliters in 1 liter. Therefore, 300 milliliters · 1000 = 0.3 liters. Choice A, 0.03 liters, is the result of dividing by 10 instead of 1000. Choice B, 3 liters, is the result of multiplying instead of dividing. Choice D, 0.003 liters, is the result of dividing by 1000 twice, which is incorrect.

Correct Answer: A

Rationale: To solve the equation, begin by distributing the 3 on the left side: 3x - 12 = 18. Next, add 12 to both sides to isolate x: 3x = 30. Finally, divide by 3 to determine the value of x: x = 10. Therefore, the correct answer is x = 10. Choice B, x = 12, is incorrect as the correct value of x is 10, not 12. Choice C, x = 5, is incorrect as it does not satisfy the equation after substitution. Choice D, x = 3, is incorrect as it does not fulfill the equation when substituted back.

Correct Answer: A

Rationale: To solve the expression, we follow the order of operations (PEMDAS). First, we divide 24 by 2 to get 12. Then, we multiply 8 by 12, which equals 96. Finally, we subtract 96 from 2: 2 - 96 = -94. Therefore, the correct answer is A, '-94'. Choices B, C, and D are incorrect as they do not follow the correct order of operations or make errors during calculation.

Correct Answer: A

Rationale: Substitute x = -2 and m = -3 into the expression: (-2) * (-3) - 2 * (-3) = 6 + 6 = 12. Therefore, the correct answer is 12. The mistake in the other choices lies in the calculation. Choice B, 6, is the result of adding the two terms instead of subtracting the second term from the first. Choice C, 8, and Choice D, 10, are also incorrect as they do not follow the correct calculation process.