Answer:
[tex]\huge\boxed{\dfrac{6}{7}-\dfrac{3}{x}=\dfrac{6x-21}{7x}}[/tex]
Step-by-step explanation:
[tex]\dfrac{6}{7}-\dfrac{3}{x}=\dfrac{(6)(x)}{(7)(x)}-\dfrac{(7)(3)}{(7)(x)}=\dfrac{6x}{7x}-\dfrac{21}{7x}=\dfrac{6x-21}{7x}[/tex]
