Question

A-b=2&ab=8 then a^3-b^3=???

Answer 1

$<b>Heya mate. (^_-). Solution below.$
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• a - b = 2


• Cubing both sides -

=> (a - b)³ = (2)³


• Using identity : (x - y)³ = x³ - y³ - 3xy(x - y)

=> a³ - b³ - 3ab(a - b) = 8

=> a³ - b³ - (3 × 8)(2) = 8

=> a³ - b³ - (3 × 8 × 2) = 8

=> a³ - b³ - 48 = 8

=> a³ - b³ = 48 + 8

=> a³ - b³ = 56


$<marquee>Hence, a³ - b³ = 56.</marquee>$
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Thank you... ;-)