1:$\overline {A}\cdot \overline {B}+A\cdot B $
2:$\overline {A}\cdot\ B+A\cdot\ \overline {B}$
3:$\left( A+B\right) \cdot \left( A+\overline {B}\right) $
4:$\left( A+B\right) \cdot \left( A+\overline {B}\right) $
5:$\overline {A}\cdot \left( A+B\right) +B\cdot \left( \overline {A}\cdot \overline {B}\right) $