I need some help on this problem:

Describe the difference between an open equation and a closed equation.

My textbook says that an open equation is one which has a variable, although it never mentions the term closed equation. I tried looking online for the meaning of this term, but I did not find anything useful. Can someone help me on this problem?

1 answer

closed: 23 = 2*5+13 always true
open: 2x+3 = 17 true only for x=7

I think