Simplify the radical expression:

√441

Determine the square of the following expression:

(√11)/7

Rationalize the denominator of the given radical expression.

35/(9 + √11)

For the following rational expression, determine its domain.

14/(a² + 9a + 14)

For the following rational expression, perform the indicated operations and simplify if necessary.

(a + b)/(8a - 7b) - 7b/(7b - 8a)