If 3x + 2y = 9 and xy = 3, find: 27x^3 + 8y^3

Question

KnowledgeBoat · Accepted Answer

Using the formula, [∵ (x \+ y)³ = x³ \+ y³ \+ 3xy(x \+ y)] So, ⇒ (3x \+ 2y)³ = (3x)³ \+ (2y)³ \+ 3 3x 2y(3x \+ 2y) ⇒ (3x \+ 2y)³ = 27x³ \+ 8y³ \+ 18xy(3x \+ 2y) Putting the value (3x \+ 2y) = 9 and xy = 3, we get ⇒ (9)³ = 27x³ \+ 8y³ \+ 18 3 9 ⇒ 729 = 27x³ \+ 8y³ \+ 486 ⇒ 27x³ \+ 8y³ = 729 \- 486 ⇒ 27x³ \+ 8y³ = 243 Hence, the value of 27x³ \+ 8y³ is 243.

Mathematics

If 3x + 2y = 9 and xy = 3, find: 27x³ + 8y³

Identities

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Mathematics

If 3x + 2y = 9 and xy = 3, find: 27x3 + 8y3