Which of the following is an open equation

5x+7=12

12 + (-8) = 4

25=5 (5)

8+0=8

5x+7+12

Step-by-step explanation:

An Open Equation is basically an equation that has many variables that can be either true or false. And they normally have a (n) mystery variable in them like x or y for example x+4=8.

You can tell by looking at the problems that three of them already have an answer set in stone for what times what equals what or what + what = what you know so using reasoning and deduction you will find out that your answer is 5x+7=12 because it has a mystery variable (x) letting you know that hey you can use more than one variable whether true or false to find out what times 5 plus 7 equals 12.