Question

Giả pt: 3-x(1-3x) = 5(1-2x)

Answer 1

`=> 3 - x + 3x^2 = 5 - 10x`

`=> 3x^2 + 9x = 2`

`=> x^2 + 3x = 2/3`.

`=> x = (-9 +- sqrt 105)/6`.

Answer 2

\(\Leftrightarrow3-x+3x^2=5-10x\)

\(\Leftrightarrow3x^2-x+3-5+10x=0\)

\(\Leftrightarrow3x^2+9x-2=0\)

\(\text{Δ}=9^2-4\cdot3\cdot\left(-2\right)=81+24=105\)

Do đó: PT có 2 nghiệm phân biệt là:

\(\left\{{}\begin{matrix}x_1=\dfrac{-9-\sqrt{105}}{6}\\x_2=\dfrac{-9+\sqrt{105}}{6}\end{matrix}\right.\)

Answer 3