Mandarin chinese is not spoken widely outside of china, yet it is spoken by more people than any other language. what makes this possible?

It is possible because the population of China is very large.

Immigration? Because many Chinese left China due to civil wars and riots? When they marry or live with locals, they might spread the knowledge of the language

Amath expression is a collection of one or more terms, which are separated by the signs ( + , - , x , / ).example :   8+b8+b  or  a−3a−3in algebra, an equation is a mathematical statement with two expressions where, each expression is separated by an equal (=) sign. variables can be present on both the sides of the equality (=) sign and we use letters to denote such variables.example 1:   x=4+2x=4+2  , [here, we can observe that the variable is present only on one side of the equation].example 2:   2x+3=x+42x+3=x+4  , [here, we can observe that the variables are present on both side of the equation].

Ansradar; im guessing here; good luck : )