Question

if x+1/x=7, then find x^3+1/x^3

Answer 1

X +1/X = 7 (X + 1/X)3 = 73 X3 + 1/X3 + 3 X (1/X) (X+ 1/X) = 343 As, ( a+ b)3 = a3+ b3+3ab(a+b) X3+ 1/X3+ 3*7 = 343 X3+ 1/X3 =343−21 X3+ 1/X3= 322