Respuesta :

Answer:

-3

Step-by-step explanation:

The given expression is:

[tex]\frac{\frac{a-3}{7} }{\frac{3-a}{21} }[/tex]

We can rewrite this as:

[tex]\frac{a-3}{7}\div \frac{3-a}{21}[/tex]

[tex]\frac{a-3}{7}\times \frac{21}{3-a}[/tex]

Factor -1 out of the first numerator:

[tex]\frac{-(3-a)}{7}\times \frac{21}{3-a}[/tex]

Cancel out the common factors;

[tex]\frac{-1}{1}\times \frac{3}{1}=-3[/tex]

Answer:

-3

Step-by-step explanation:

that's just the way it be.