1, formula "ab+ b=ba?" According to the law of multiplication and exchange, we can know that AB = BA 2.

2. Therefore, it can be inferred that b=ab-ba=0.

3, 0 times any number equals 0, so a here can be any number.

Extended data:

Multiplication operation properties:

1, multiplicative commutative law: AB = BA

2. Multiplicative associative law: ABC = a (BC); );

3. Multiplication and distribution law: a(b+c)=ac+bc.