Question

if x=3+root 5÷2,show that x+1÷x=3 and find x cube+1÷x cube=?​

Answer 1

Answer:

x+1x=3

(x+1x)3=33

x3+3.x2.1x+3.x.1x2+1x3=27

(x3+1x3)+3.x2.1x+3.x.1x2=27

x3+1x3+(3x+3x)=27

x3+1x3+3(x+1x)=27

x3+1x3+3×3=27

x3+1x3+9=27

x3+1x3=18

Therefore the answer is 18