Answer thos question plzz
If (x-1/x)=7 , then the value of (x)cube-1/(x)cube=?
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x - 1/x = 7 -----------(1)
we know,
a³ - b³ = (a - b)³ + 3ab(a - b) use this here,
x³ - 1/x³ = (x - 1/x)³ - 3.x.1/x(x - 1/x)
=(x - 1/x)³ - 3(x - 1/x)
now, put equation (1)
= (7)³ - 3(7)
= 343 - 21
= 322
hence, x³ - 1/x³ = 322
we know,
a³ - b³ = (a - b)³ + 3ab(a - b) use this here,
x³ - 1/x³ = (x - 1/x)³ - 3.x.1/x(x - 1/x)
=(x - 1/x)³ - 3(x - 1/x)
now, put equation (1)
= (7)³ - 3(7)
= 343 - 21
= 322
hence, x³ - 1/x³ = 322
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