Đáp án: $x=\dfrac{-2a+9}{a-3}$
Giải thích các bước giải:
Ta có :
$\dfrac{x-4}{3}-\dfrac{x+3}{a}+2=0$
$\to\dfrac{x}{3}-\dfrac43-\dfrac{x}{a}-\dfrac3a+2=0$
$\to\dfrac{x}{3}-\dfrac{x}{a}=\dfrac43-2+\dfrac3a$
$\to x\left(\dfrac{1}{3}-\dfrac{1}{a}\right)=-\dfrac23+\dfrac3a$
$\to x=\left(-\dfrac23+\dfrac3a\right):\left(\dfrac{1}{3}-\dfrac{1}{a}\right)$
$\to x=\dfrac{-2a+9}{3a}:\dfrac{a-3}{3a}$
$\to x=\dfrac{-2a+9}{3a}.\dfrac{3a}{a-3}$
$\to x=\dfrac{-2a+9}{a-3}$
