Question

What is the least common denominator of the rationalexpressions below?

Answer 1

To find:

The least common denominator

Solution:

First factorise the denominators of both the fractions and find the common factors along with the uncommon factors.

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

So, the least common denominator is:

$x(x-7)(x+3)$

Thus, option A is correct.