Question

Calculati x²+ 1 supra x² , stiind ca x + 1 supra x =3 , unde x∈ R*

Answer 1

x+1/x=3
x+1=3x
2x=1
x=1/2
x la patrat+1/x patrat= (1/4+1)/1/4=5/4:1/4=5
raspuns;5

Answer 2

[(x+1)/x]^2=x^2+2x+1/x^2

x+1=3x

3x-x=1

2x=1

x=1/2

(1/4+1/2+1)/ 1/4

(2/8+4/8+8/8)*4

14/8*4

14/2

9