=>21x^2+14x-18x-12=6x^2-3x+4x-2
=>21x^2-4x-12-6x^2-x+2=0
=>15x^2-5x-10=0
=>3x^2-x-2=0
=>3x^2-3x+2x-2=0
=>(x-1)(3x+2)=0
=>x=1 hoặc x=-2/3
`(3x+2)(2x-1)=(7x-6)(3x+2)`
`<=> (3x+2)(2x-1)-(7x-6)(3x+2)=0`
`<=>(3x+2)(2x-1-7x+6)=0`
`<=>(3x+2)(-5x+5)=0`
\(\Leftrightarrow\left[{}\begin{matrix}3x+2=0\\-5x+5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=-2\\-5x=-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{2}{3}\\x=1\end{matrix}\right.\)
Vậy pt có tập nghiệm \(S=\left\{-\dfrac{2}{3};1\right\}\)
` @ \color{Red}{Lemon}`
(3x + 2)(2x - 1) = (7x - 6)(3x + 2)
⇔ (3x + 2)(2x - 1) - (7x - 6)(3x + 2) = 0
⇔ (3x + 2)(2x - 1 - 7x + 6) = 0
⇔ (3x + 2)(-5x + 5) = 0
⇔ 3x + 2 = 0 hoặc -5x + 5 = 0
*) 3x + 2 = 0
⇔ 3x = -2
x = -2/3
*) -5x + 5 = 0
⇔ 5x = 5
⇔ x = 1
Vậy S = {-2/3; 1}
