Correct Answer: A

Rationale: To convert a percentage to a decimal, move the decimal point two places to the left. Therefore, 58% as a decimal is 0.58. Choice B, 5, is incorrect as it does not represent the conversion of a percentage to a decimal. Choices C and D, both 0, are also incorrect as they do not reflect the correct conversion of 58% to a decimal.

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.

Correct Answer: C

Rationale: To add the fractions, first find a common denominator. The least common denominator between 3 and 9 is 9. Convert 2/3 to 6/9 then add 6/9 + 4/9: = 10/9

Correct Answer: A

Rationale: To find x, we set up the proportion 15:x = 3:8. Cross multiply to get 15*8 = 3*x, which simplifies to 120 = 3x. Dividing by 3 on both sides gives x = 40. Therefore, x=40 is the correct answer. Choices B, C, and D are incorrect because they do not match the correct calculation. Option B results from incorrectly dividing 15 by 3 instead of multiplying it by 8. Option C comes from dividing 15 by 3, and Option D is the result of dividing 15 by 8 instead of multiplying by 3.

Correct Answer: A

Rationale: To convert a percentage to a decimal, move the decimal point two places to the left. Therefore, 58% as a decimal is 0.58. Choice B, 5, is incorrect as it does not represent the conversion of a percentage to a decimal. Choices C and D, both 0, are also incorrect as they do not reflect the correct conversion of 58% to a decimal.