1. I'll just try this problem...I don't know if I'll get it !
Let \(\sqrt{49-20\sqrt{6}}=a-b\).
We can square both sides to get, \(49-20\sqrt{6}=(a-b)^2\).
Expanding this, gives us \(49-20\sqrt{6}=a^2+b^2-2ab\).
Now, by a bit of matching, we can see that \(a^2-b^2=49\) and \(-2ab=-20\sqrt{6}\) (Same thing as \(2ab=20\sqrt{6}\))
This might be a bit of tedious work, but by a bit of inspection \(a=5\) and \(b=2\sqrt{6}\) work.
Thus, the answer is \(a-b=\boxed{5-2\sqrt{6}}.\)
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