Check whether `7sqrt(5),7/(sqrt(5)),sqrt(2)+21 ,pi-2`are irrational numbers or not.

Explanation

To determine whether the numbers \(7\sqrt{5}\), \(\frac{7}{\sqrt{5}}\), \(\sqrt{2} + 21\), and \(\pi - 2\) are rational or irrational, we will analyze each number step by step.

### Step 1: Check \(7\sqrt{5}\)

1. **Identify \(\sqrt{5}\)**:
- The square root of 5 (\(\sqrt{5}\)) is known to be an irrational number because it cannot be expressed as a fraction of two integers.

2. **Multiply by 7**:
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