• √27 = √(3.3.3) = 3√3
• √12 = √(2.2.3) = 2√3
• √48 = √(3.4.4) = 4√3
• A = 2*(3√3) + 5*(2√3) - 3*(4√3) = 6√3 + 10√3 - 12√3 = 4√3

Vậy A = 4√3.

• (2 - 3)² = (-1)² = 1
• (1 - √3)² = 1 - 2√3 + 3 = 4 - 2√3
• B = √1 + √(4 - 2√3)

• Để tính √(4 - 2√3), chúng ta sẽ sử dụng công thức: √(a ± b√c) = √[(√x ± √y)²] với x và y là các số hữu tỉ thỏa mãn hệ phương trình: * x + y = a * 2√xy = b√c

  Trong trường hợp này, a = 4, b = -2, c = 3. Ta tìm được x = 3 và y = 1.

• Tiếp tục tính toán B: B = 1 + √[(√3 - √1)²] = 1 + |√3 - 1| = 1 + (√3 - 1) (vì √3 > 1) = √3

Vậy B = √3

B

• Original sentence: "Why didn't you follow my advice?" he said.
• Indirect speech: We need to change the tense of the verb "didn't follow" to the past perfect tense.
• Correct answer: D. He asked me why I hadn't followed his advice.

• Original sentence: "If I were you, I would take the job," said my room-mate.
• Indirect speech: This is a conditional sentence, and we need to maintain the same tense structure.
• Correct answer: B. My room-mate advised me to take the job.

• Original sentence: You talk more than you work.
• Indirect speech: The teacher wishes that you worked more than you talked. This is a wish about the present, so we use the past simple tense.
• Correct answer: B. you worked more than you talked.