What is the factorization of 121b4-49

Since 121 is a perfect square, 12x12, and 49 is a perfect square, 7x7, and b^4 is a perfect square, b^2xb^2, you have what's called the difference of perfect squares. These factor into the sum and difference of the square roots. So (11b^2+7) (11b^2-7)