Simplify
(5x – 7y)3 +(5x + 7y)3
(5x – 7y)3 +(5x + 7y)3 = [(5x)3 -{3 ×(5x)2 × (7y)} +{3 ×(5x)×(7y)2} -(7y)3] + [(5x)3 +{3 ×(5x)2 ×(7y)} +{3 ×(5x)×(7y)2} + (7y)3]
{∵(a + b)3 = a3 + 3a2b + 3ab2 + b3 and(a – b)3 = a3 – 3a2b + 3ab2 – b3}
= [ 125x3 –{3 × 25x2 × 7y } +{3 × 5x × 49y2 } – 343y3 ] + [ 125x3 +{3 × 25x2 × 7y } +{3 × 5x × 49y2 } + 343y3 ]
= [ 125x3 – 525x2y + 735xy2 – 343y3 ] + [ 125x3 + 525x2y + 735xy2 + 343y3 ]
= 125x3 – 525x2y + 735xy2 – 343y3 + 125x3 + 525x2y + 735xy2 + 343y3
= 250x3 + 1470xy2
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Generated by AI. May contain inaccuracies — always verify with your textbook.