3/7(b+2)-6/7(b-2)=
[tex] \frac{3}{7(b+2)} -\frac{6}{7(b-2)} [/tex]
Here we find lcd first
lcd = 7(b+2)(b-2)
converting into lcd form we get,
[tex] \frac{3(b-2)}{7(b+2)(b-2)} -\frac{6(b+2)}{7(b-2)(b+2)} [/tex]
=[tex] \frac{(3b-6)}{7(b+2)(b-2)} -\frac{(6b+12)}{7(b-2)(b+2)} [/tex]
=[tex] \frac{3b-6-6b-12}{7(b+2)(b-2)} [/tex]
=[tex] \frac{-3b-18}{7(b+2)(b-2)} [/tex]
