If x + y = 10 and xy = 21, find the value of x^3 + y^3.
A350
B370
C400
D430
Explanation
x^3 + y^3 = (x+y)(x^2-xy+y^2) = (x+y)((x+y)^2-3xy) = 10(100-3*21) = 10(100-63) = 10*37 = 370.
Exam Relevance
- Topic: Algebra
- Subtopic: Identities

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