Question

x+1/x=7 then x^3+1/x^3 please help me tomorrow I has exam​

Answer 1

x+(1/x)=7

cubing on both sides,

[x+(1/x)]^3=7^3

x^3+(1/x)^3+(3×x×1/x)×( x+(1/x))= 316

x^3+(1/x)^3+3 (x+1/x)= 316

x^3+(1/x)^3= 316-3×(x+1/x)

we know that (x+1/x)=7,

so x^3+(1/x)^3= 316-3×7

x^3+(1/x)^3= 316-21

x^3+(1/x)^3= 295

HOPE IT HELPS...

All the very best for your exams...