When solving for the difference of two squares (DOTS), make sure that:
(a) the first and second term are perfect squares, meaning they have a perfect square root;
(b) the exponent must always be even;
(c) at least one term must be negative
(a + b)(a - b) = a² - b² then therefore, the factors of a² - b² are (a + b)(a - b).
Example:
[tex]25 x^{2} - 49[/tex]
Find the square root of the first and second term
25x² = 5x
49 = 7
The answer is (5x - 7)(5x + 7).
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