Number of solutions, step by step

Some equations have one answer, some none at all, and some are true for every number.

The question

How many solutions?

17x + 25 = 25 + 17x

17x + 25 = 25 + 17x
17x + 25 = 25 + 17x
x is gone
25 = 25is true
infinitely many solutions
  1. Do not start by hunting for x. Ask a smaller question first: what is left when the x terms are collected on one side?
  2. Both sides have the SAME number of x, so taking it off both sides removes x completely. That is not a mistake — it is the answer arriving early.
  3. What is left is 25 = 25, which is true whatever x is. So every number works — infinitely many solutions.

How it works.

  1. 01

    Do not start by hunting for x. Ask a smaller question first: what is left when the x terms are collected on one side?

  2. 02

    Both sides have the SAME number of x, so taking it off both sides removes x completely. That is not a mistake — it is the answer arriving early.

  3. 03

    What is left is 25 = 25, which is true whatever x is. So every number works — infinitely many solutions.