Answer:
1. The number zero (0) is the additive identity for real numbers as adding it to any real number doesn't change the number.
2. a(b+c) = ab + ac or a(b-c) = ab-ac is the distributive property as a is distributed to b and then c.
3. An Equation with more than one variables is called literal equation. The variables are known in literal equations. These kind of equations are usually used to represent time, distance etc.
4. The number 1 is the multiplicative identity for real numbers as multiplying any real number with 1, other than zero, doesn't change the number.
5. The reciprocal of a number such that x is a number other than zero and 1/x is the reciprocal and the product of x and 1/x is equal to 1 then 1/x is called the multiplicative inverse of x.