Question

if x + 2y = 6 and x y = -2, find x3 + 8y3

, stating the identities used​

Answer 1

Answer:

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Identity :- (x+y)³ = x³ + y³ + 3xy(x+y)

x = x

y = 2y

(x+2y)³ = x³ + (2y)³ + 3(x)(2y)(x+2y)

(6)³ = x³ + 8y³ + 6xy(6)

216 = x³ + 8y³ + 6(-2)(6)

216 = x³ + 8y³ - 72

x³ + 8y³ = 288

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Step-by-step explanation: