Factor [tex]a^{2} - 121 b^{2} [/tex]
In this term, we're going to factor it by using DOTS or the difference of two squares.
We must always remember that DOTS consist of the following:
The first and second terms should be a perfect square;
The sign of the second term should always be negative (-).
[tex] a^{2} - b^{2} = (a - b)(a + b)[/tex]
So back to the given...
[tex] a^{2} - 121b^{2} [/tex]
The first and the second term are perfect squares so the next step is to find their square roots; so,
The answer is: [tex](a - 11b) (a + 11b)[/tex]
