Question

Factor problems 9 - 12 by using the difference of squares method.

Answer 1

Answer:  9) D   10) E   11) E   12) D

Step-by-step explanation:

Notes: The difference of squares is    a² - b² = (a - b)(a + b)

To solve, take the square root of the first term and the square root of the last term. The factors are the sum and difference of those values.

9) x² - 4

   a = √x² = x        

   b = √4 = 2

   Factors: (x - 2)(x + 2)

   Answer: D

10) x² - 25

    a = √x² = x        

    b = √25 = 5

    Factors: (x - 5)(x + 5)

    Answer: E

11) 36x⁴ - 4x²

   Factor out the common term (4x²) --> 4x²(9x² - 1)

   a = √9x² = 3x        

   b = √1 = 1

   Factors: 4x²(3x - 1)(3x + 1)

   Answer: E

12) x² + 100

    The plus (+) sign means this is not in the form of a² - b²

    so it cannot be factored over the Real #s using this method

    Answer: D