cho 3y - x = 6. Giá trị biểu thức A = [tex]\frac{x}{y - 2} + \frac{2x-3y}{x-6} + 2^{3}[/tex] bằng....
$3y-x=6\Rightarrow x=3y-6
\\\Rightarrow A=\dfrac{3y-6}{y-2}+\dfrac{2(3y-6)-3y}{3y-6-6}+2^3
\\=\dfrac{3(y-2)}{y-2}+\dfrac{6y-12-3y}{3y-12}+8
\\=3+1+8
\\=12$