Question

7(x + 1/x) - 2 (x^2 + 1/X^2) = 9

Answer 1

7(x + 1/x) - 2 (x^2 + 1/X^2) = 9

7x+7/x-2x^2-2/x^2=9

6x+7-x^2-2=9

6x+7-x^2-2-9=0

x^2-6x+=0

D=36-20=16=4^2

x1=(36-4)/2=16

x2=(36+4)/2=20

ответ:  16;20