Question

to prove 5 minus 2 root 7 is an irrational number​

Answer 1

subtracting rational numbers from irrational number is always irrational

Answer 2

let 5-2root7 be rational number.

as we know that ,

rational number=p/q

so,

5-2root7=p/q

-2root 7 =(p/q-5)

root7=(p/q-5)÷2

since,

root7 is rational number.

But,

it is fact that root 7 is irrational number.

so,

5-root7 is irrational number.