Question
If, ( a + b = 8 ) and ( a² + b² = 40 ), then find the
value of (a³ + b³).Solution
( a + b = 8 )
( (a + b) ² = 8² )
( a² + b² + 2ab = 64 )
( 40 + 2ab = 64 )
( 2ab = 24 ab = 12 )
( a³ + b³ = (a + b)(a² + b² - ab)) = 8 (40 - 12) = 8 * 28 = 224
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