Question

2
-3
Find the least common denominator of
x2 - 4x – 21
and
x² - 4

Answer 1

(x+3)(x-7) & (x+2)(x-2)

Explanation:

Answer 2

LCD = (x - 7)(x + 3)(x + 2)(x - 2)

Explanation:

First, we factor each polynomial.

x^2 - 4x - 21 = (x - 7)(x + 3)

x^2 - 4 = (x + 2)(x - 2)

There are 4 different factors and none are in common, so the LCD is the product of all the factors.

LCD = (x - 7)(x + 3)(x + 2)(x - 2)