Chapter 3.1, Problem 34E

To determine

To compare and contrast: The two methods and explain what do you notice.

Answer to Problem 34E

The solution is $x=27$ . In first case no negative sign comes into play but mine transformation dare in first case than second case.

Explanation of Solution

Given information: $18-2x=-36$,

Calculation: First solve by adding $2x$ to each side,

  $\begin{array}{l}18-2x=-36\\ \Rightarrow 18-2x+2x=-36+2x\\ \Rightarrow 18=-36+2x\\ \Rightarrow 18+36=2x\\ \Rightarrow 2x=54\\ \Rightarrow x=\frac{54}{2}\\ \Rightarrow x=27\end{array}$

Second, solve by subtracting $18$ from each side

  $\begin{array}{l}18-2x=-36\\ \Rightarrow 18-2x-18=-36-18\\ \Rightarrow -2x=-54\\ \Rightarrow 2x=54\left[\begin{array}{l}\text{multipling both side}\\ \text{with negative sign,}\end{array}\right]\\ \Rightarrow x=\frac{54}{2}\\ \Rightarrow x=27\end{array}$

Hence, The solution is $x=27$ . In first case no negative sign comes into play but mine transformation dare in first case than second case.