`\color{pink}{#Bơ}`

Áp dụng đl Vi-et, ta có:

`{(x_1+x_2 = 5),(x_1x_2=4):}`

`C = (x_1\sqrt{x_2} - x_2\sqrt{x_1})/(x_1^2 + 5x_2)`

`=> C = (x_1x_2(x_1+x_2) - 2x_1x_2\sqrt{x_1x_2})/((x_1+x_2)^2 - x_1x_2`

`=> C = (4.5-2.4.\sqrt 4)/(5^2 - 4)`

`=> C = 2/21`

Vậy `C = 2/21`

  `\color{#1AD5F7}{⋆⟡D}\color{#1AD5F7}{r}\color{#4DA6E6}{a}\color{#668EDD}{g}\color{#8077D5}{o}\color{#995FCD}{n}\color{#EA2F90}{⟡⋆}`