Question

if x=(7+5*root2), then x²+1/x²=??​

Answer 1

Answer:

198

Step-by-step explanation:

x = 7+5√2

1/x = 1/(7+5√2) × (7-5√2)/(7-5√2)

    = 7-5√2 / -1 = 5√2-7

x+1/x = 7+5√2 + 5√2 - 7

x+1/x = 10√2

(x+1/x)² = x² + 1/x² + 2(x)(1/x) = x²+1/x²+2

(10√2)² = x²+1/x²+2

200 = x²+1/x²+2

x²+1/x² = 198

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Answer 2

Step-by-step explanation:

here we should add & subtract 2

then (x+1/x)-2

(x+1/x)squre -2

plz mark me tnx