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What is the least common denominator of the expression below

What is the least common denominator of the expression below-example-1

2 Answers

4 votes

We must factor the denominators first. And to factor a quadratic equation, you need its roots.

We will use the fact that any quadratic equation with leading coefficient 1, i.e. in the form
x^2+bx+c has the following properties:

  • The sum of the roots is
    -b
  • The product of the roots is
    c

So, for the first denominator, we're looking at two numbers such that their sum is -4 and their product is -12. It's easy to find out that those numbers are 2 and -6.

Similarly, for the second denominator, we're looking at two numbers such that their sum is -7 and their product is 6. It's easy to find out that those numbers are -1 and -6.

So, you can rewrite the expression as follows:


(x^2+6)/((x-2)(x+6))+(7x)/((x+1)(x+6))

The least common denominator is formed by the factors of the two denominators, and you have to select repeating ones only once.

User Ctor
by
3.8k points
7 votes

Answer:

answer: B (x+6)

Explanation:

hello :

x²+7x+6 =(x+6)(x+1)

x²+4x-12=(x+6)(x-2)

the least common denominator is : (x+6).......( answer: B)

User Vadym K
by
4.4k points