Chapter 11.4, Problem 5STP

What is the sum $\frac{a-1}{ab{c}^3}+\frac{3-b}{ab{c}^3}$?

$A\frac{a-b-3}{ab{c}^3}B\frac{a-b+2}{ab{c}^3}C\frac{a-4+b}{ab{c}^3}D\frac{-3}{c^3}$

To determine

To choose the correct answer.

Answer to Problem 5STP

B) $\frac{a-b+2}{ab{c}^3}$

Explanation of Solution

Given information:

What is the sum $\frac{a-1}{ab{c}^3}+\frac{3-b}{ab{c}^3}$ ?

A) $\frac{a-b-3}{ab{c}^3}$

B) $\frac{a-b+2}{ab{c}^3}$

C) $\frac{a-4+b}{ab{c}^3}$

D) $\frac{-3}{c^3}$

The sum is:

  $\begin{array}{l}\frac{a-1}{ab{c}^3}+\frac{3-b}{ab{c}^3}\\ =\frac{a-1+3-b}{ab{c}^3}\\ =\frac{a-b+2}{ab{c}^3}\end{array}$

Hence, the correct answer is $\frac{a-b+2}{ab{c}^3}$ .