(2x - 3y)⁴ = ... The coefficient of x³y is:
Solution
(a+b)⁴ = Σ C(4,r) a^(4-r) b^r. For x³y: r=1 (power of y). Coefficient = C(4,1) × (2x)³ × (-3y)¹ = 4 × 8 × (-3) = -96. C(4,3) = 4, C(4,1) = 4 (same). So C(4,1) × 2³ × (-3) = -96.
About this question
Subject: Mathematics · Chapter: Binomial Theorem · Topic: Binomial Expansion
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