Respuesta :

u just distribute and then simplify
21f - 14g + 14g - 14f
-14g and 14g cancels out
21f - 14f is 7f
7 (3f - 2g) + 14 (g - f)

I believe you want to calculate the result, since you are mentioning nothing.

If so then 21f -14g + 14g -14f = 7f