The coefficient of x3y in ( x + 2y)

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Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

The coefficient of x³y in ( x + 2y) × (5x + y)³ is :

Options:

-150

250

325

Correct Answer:

325

Explanation:

Given = (x + 2y) × (5x + y)³

= (x + 2y) × (5x + y)³

= (x + 2y) × (125x³ + y³ + 75x²y + 15xy²)

= 125x⁴ + xy³ + 75x³y + 15x²y² + 250x³y + 2y⁴ + 150x²y² + 30xy³

Coefficient of x³y = 75 + 250 = 325