Prove that 2√7 is irrational.
Let us assume that 2√7 is a rational number.
2√7= 2√7×√7√7=2√77( Rationalising)
Now,2√77=pq ( as rational no. can be written in the form of pq)
2√7=7pq
√7=7p2q
Here LHS is irrational but RHS is rational.
This contradicts the statement.
Our assumption is wrong.
2√7 is an irrational number.