1

a·(b + c)=

a·b +a·c
a·b +b·c
a+b·c
b·a +b·c

2

a·(b + c) =

c·a+b
(c+b)·a
c·(b+a)
b·a+b·c

3

a·b· (b + c )=

a·b + a·b·c
a·b·c + a·b²
a·b +c
a·c+b²

4

(a + b)·(c + d)

a·c+b·c+d
(a+b)·c+(a+b)·d
(c+d)·a + b + a
(a+b)·c+d