By not using the digit 0, John has 9 digits left to choose from. By not using the letter m, John has 25 letters left to choose from.
The password pattern is <letter><letter><digit><digit><digit><digit>. Use the Multiplication Principle:
25 x 25 x 9 x 9 x 9 x 9 = 4,100,625
First example:
Subtract the 8n on both sides to get the variable on one side of the equation. Do the same for the regular numbers. Then divide by -3.

This should be your final answer.
Second Example:
Do the same thing as explained in Example 1. Here's some work to help guide you.

That should be your final answer here.
Third Example:

Hope this helps and its understandable! Let me know if you still don't understand.
Answer:
x = 11.25
Step-by-step explanation:
-6 = 0.8x - 15
Add 15 to both sides;
-6 + 15 = 0.8x - 15 + 15
9 = 0.8x
Divide both sides by 0.8;
x = 11.25
Answer:
0
Step-by-step explanation: