The definition is A combination of variables, numbers, and at least one operation.
Expression
It is an algebraic expression.
Equation
An expression is a mathematical phrase that combines numbers, variables, and at least one operation, such as addition, subtraction, multiplication, or division. For example, (3x + 5) is an expression that includes the variable (x), the number (5), and the operation of addition. Expressions do not include equality signs, making them distinct from equations. They can be simplified or evaluated for specific values of the variables.
complex numbers
The definition is A combination of variables, numbers, and at least one operation.
Expression
A combination of variables,numbers,and at least one operation!
The term for that is algebra.
Expression
An expression.
That sounds like the description of an "expression", except for one detail: an expression MAY have operations, but also, it may not, since numbers and variables are themselves expressions.
It is an algebraic expression.
An equation.
Equation
It is an algebraic expression.