Question

solve this problem 7 one

Answer 1

Frd help me also please

Answer 2

let us assume that 7-2root5 is rational ....
then ,
7-2root5 = a/b (for a,b = coprime and bnot equla to zero)
thus , 2root5=7-a/b=7b-a/b
root5= 7b-a/2b

Here , root 5 is irrational ,
but 7b-a/2b is rational
Thus our assumption that 7-2root5 is irrational is wrong .
Hence proved .
:)