Answer:
This proof can be done by contradiction.
Let us assume that 2 - √2 is rational number.
So, by the definition of rational number, we can write it as

where a & b are any integer.
⇒ 
Since, a and b are integers
is also rational.
and therefore √2 is rational number.
This contradicts the fact that √2 is irrational number.
Hence our assumption that 2 - √2 is rational number is false.
Therefore, 2 - √2 is irrational number.
20\2=10
10\2=5
5\2=2.5
2.5\2=1.25
Answer:
the left hand side is equals to |13| which is nothing but 13 so is the right hand side.
42•48=2,016. Hope this helped!