Question

Prove (√a+√b) (√a-√b) is rational

Answer 1

Answer:

Let a and b be be real numbers

So

(√a+√b) × (√a-√b)

by formula (a+b)×(a-b) = a^2 - b^2)

= (√a)^2 - (√b)^2

= a - b

Real number subtracted from real number is real number

Hence proved