Prove that(1 + cb)(x + a) = (a + x)(bc + 1)
You can use:

A+ (associative property of addition)

Ax (associative property of multiplication)

C+ (commutative property of addition)

Cx (commutative property of multiplication)

(1 + cb)(x + a) = (1 + cb)(a + x)

(1 + cb)(x + a) = (1 + bc)(a + x)

(1 + cb)(x + a) = (bc + 1)(a + x)

(1 + cb)(x + a) = (a + x)(bc + 1)