Question

Charlie solved an equation. as shown below:

Answer 1

Charlie's solution is incorrect.  He did step 2 incorrectly.  Because the equation is 5x = 30, he needs to divide by 5 instead of subtract 5 from both sides.

If this was done correctly, it would like like this:

Step 1: 5x = 30
Step 2: x = 30/5
Step 3: x = 6

This equation will only have one solution, x = 6.