Check Identify each as an equation or and expression.
21x-13 +11
Equations
Expressions
x= 2x+5
-3.7x-13
12x + 5
12x = 5 + 3
3x + 1 = -2.1

Step-by-step explanation:

An equation contains a sign equality (=) between two expressions.

And an expression is a simple algebraic statement.

By these definitions,

          Equations                          Expressions

         x = 2x + 5                            21x - 13 + 11x

                                    -3.7x - 13  

         3x + 1 = -2.1