The coefficient of x in (x −

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Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

The coefficient of x in (x − 3y)³ is:

Options:

3y²

27y²

−27y²

−3y²

Correct Answer:

27y²

Explanation:

(a - b)³ = a³ - b³ - 3ab(a-b)

(x – 3y)³

= x³ – (3y)³ – 3 × x × 3y (x – 3y)

= x³ – 27y³ – 9x²y + 27xy2

So, the coefficient of x = 27y²