(x+1/x)^3 = x^3 + 1/x^3 + 3 (x+1/x) x*1/x => x^3 + 1/x^3 = 8000 - 3*20 = 7940

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(x+1/x)^3 = x^3 + 1/x^3 + 3 (x+1/x) x*1/x => x^3 + 1/x^3 = 8000 - 3*20 = 7940

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x^2+(1/x)^2+2 x x x 1/x=400

x^2+1/x^2+2x/x=400

thereforex^2+1/x^2=400-2=398

sry tried the second one but im not able to do