Correct Answer: C

Rationale: The correct order of operations dictates solving division and multiplication before addition and subtraction. Therefore, following the order: (12 · 3) 4 - 1 + 23 = 4 4 - 1 + 23 = 16 - 1 + 23 = 38. Choice A (6) results from adding and subtracting before division and multiplication. Choice B (21) results from incorrect placement of parentheses. Choice D (23) is the last number in the expression and does not reflect the cumulative result of the operations.

Correct Answer: A

Rationale: The correct answer is A: 'One.' When the number 1 is raised to any power, the result is always 1. This is a fundamental mathematical property where any number raised to the power of 0 equals 1. Choices B, C, and D are incorrect. Choice B 'Itself' is vague and does not provide a clear mathematical result. Choice C 'Zero' is incorrect as 1 raised to any power is not zero. Choice D 'Two' is incorrect as the result of raising 1 to any power is always 1, not 2.

Correct Answer: A

Rationale: To convert yards to feet, you need to know that 1 yard is equal to 3 feet. Therefore, to convert yards to feet, you multiply the number of yards by 3. To convert feet to yards, you divide the number of feet by 3. Choice A correctly states that you should multiply yards by 3 to get feet and divide feet by 3 to get yards. Choices B, C, and D provide incorrect conversion factors, leading to inaccurate results.

Correct Answer: A

Rationale: To find the expression representing the length of the rectangle in terms of x, we need to consider that the length is six less than two times the width. If we denote the width as x, the length can be expressed as 2x - 6. Therefore, the correct expression is 2x-6 (choice A). Choice B, 6-2x, represents the width subtracted from 6, not the length. Choice C, 6x-2, is not derived from the given information about the relationship between the width and length. Choice D, 3x-4, is not consistent with the relationship provided in the question.

Correct Answer: D

Rationale: The correct answer is D: 17.8 cm. To convert inches to centimeters, you can use the conversion factor 1 inch = 2.54 cm. Therefore, 7 inches is equal to 7 * 2.54 = 17.78 cm, which rounds to 17.8 cm. Choices A, B, and C are incorrect because they do not correspond to the correct conversion of 7 inches to centimeters.