Question

Find the least common denominator for these two rational expressions. B/b^2 -64 -7b/b^2+7b-8

Answer 1

The least common denominator is (b-8)(b+8)(b-1)

Explanation:

We are given expression as

`(b)/(b^2-64)-(7b)/(b^2+7b-8)`

Firstly, we will factor both denominators

`b^2-64=b^2-8^2=(b-8)(b+8)`

`b^2+7b-8=(b+8)(b-1)`

so, we can plug it back

`(b)/((b-8)(b+8))-(7b)/((b+8)(b-1))`

First term denominator is

(b-8)(b+8)

Second term denominator is

(b+8)(b-1)

So,

Least common denominator will be

(b-8)(b+8)(b-1)

So, we get

`LCD=(x-8)(x+8)(x-1)`