Are bought x biros at 8, and (x+4) rulars at 20 each, he spend less than 200. form an inequality for the statement and solve it?

The commutative property basically allows you to move numbers/variables/etc around and still get the same answer. You can only do this with addition and multiplication. Eg. a+b = b+a OR a x b = b x a

Distributive law, in mathematics, the law relating the operations of multiplication and addition, stated symbolically, a(b + c) = ab + ac; that is, the monomial factor a is distributed, or separately applied, to each term of the binomial factor b + c, resulting in the product ab + ac. (https://www.britannica.com/topic/distributive-law)

Associative law, in mathematics, either of two laws relating to number operations of addition and multiplication, stated symbolically: a + (b + c) = (a + b) + c, and a(bc) = (ab)c; that is, the terms or factors may be associated in any way desired. (https://www.britannica.com/topic/associative-law)

Here's a video that explains the basics: https://www.youtube.com/watch?v=x9hoPIMNPw4