Answer:
Lets firts mention that the rule presented in the question does not apply for all real numbers
But, we can see that in some cases it might be true.
Let
a = 1
b = 0
√1 + √0 = 1 + 0 = 1
Likewise,
√(1 + 0) = √(1) = 1
And we see that the result is the same.
