x = a - \(\sqrt {7}\) y = a z = a

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Home Questions 3NZVEDC258

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

x = a - \(\sqrt {7}\)

y = a

z = a +\(\sqrt {7}\)

then x³ + y³ + z³ - 3xyz = ?

Options:

45a

27a

63a

Correct Answer:

63a

Explanation:

If x, y and z are in A.P

then x³ + y³+ z³ - 3xyz = 9 × mid term × (a)²

= 9 × a × (\(\sqrt {7}\))²

= 63a