Question

x2+1/x2=7 then the value of x3+1/x3

Answer 1

Step-by-step explanation:

x²+1/x²+2-2=7

add and subtract 2 on the left side of the equation

(x+1/x)²=9

now taking square root

(x+1/x)=3--(1)

now cube both sides

(x+1/x)³=3³

x³+1/x³+3(1)(x+1/x)=27

using eq 1

x³+1/x³+3(3)=27

x³+1/x³=27-9

x³+1/x³=18