if x=9+4√5,findx+1/x
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x = 9 + 4√5
1/x = 1/9+4√5 = 1(9-4√5)/(9+4√5)(9-4√5)
= 9 - 4√5 / (9)² - (4√5)²
= 9 - 4√5/ 81 - 80 = 9 - 4√5/1 = 9- 4√5
= x + 1/x
= 9 + 4√5 + 9 - 4√5 = 18
1/x = 1/9+4√5 = 1(9-4√5)/(9+4√5)(9-4√5)
= 9 - 4√5 / (9)² - (4√5)²
= 9 - 4√5/ 81 - 80 = 9 - 4√5/1 = 9- 4√5
= x + 1/x
= 9 + 4√5 + 9 - 4√5 = 18
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