Question

Please answer this question as fast as possible please please please please please please... class9 please answer..maths​

Answer 1

Answer:

a) x=3+2√2

x²+1/x²=(3+2√2)²+1/(3+2√2)²

=(9+8+12√2)+ 1/(9+8+12√2)

=17+12√2 + 1 /17+12√2

=(17 +12√2)(17+12√2) +1/17+12√2

=289+288+408√2 +1 /17+12√2

=578+408√2/17+12√2

=34(17+12√2)/17+12√2

=34

b)x=2+√5

x²+ 1/x²=18

(2+√5)² +1/(2+√5)²

4+5+4√5 + 1/9+4√5

9+4√5 +1/9+4√5

(9+4√5)(9+4√5) +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

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