Question

if x=√5+2,then find the value of x²+1/x²​.
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Answer 1

Answer:

18

Step-by-step explanation:

x^2+1/x^2

(√5+2)^2+1/(√5+2)^2

5+4+4√5+1/5+4+4√5

9+4√5+1/9+4√5

(9+4√5)^2+1÷9+4√5

81+80+72√5+1÷9+4√5

162+72√5÷9+4√5

18(9+4√5)÷9+4√5

18(1)

18