Show that `A sub B` then C- `B sub C- A `

Explanation

To show that if \( A \subseteq B \), then \( C - B \subseteq C - A \), we will follow these steps:

### Step 1: Understand the Definitions
- **Subset**: A set \( A \) is a subset of set \( B \) (denoted \( A \subseteq B \)) if every element of \( A \) is also an element of \( B \).
- **Set Difference**: The difference of two sets \( C - B \) consists of elements that are in \( C \) but not in \( B \).

### Step 2: Assume \( A \subseteq B \)
Given that \( A \subseteq B \), we know that every element \( x \) in \( A \) is also in \( B \).
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