Question

Your friend solved the equation $18-2x=-36$by first adding 2x to each side of the equation. You solved the equation by subtracting 18 from each side as the first step. Compare and contrast the two methods. What do you notice?

Short answer

The solution of the is$x=27$

Step-by-step solution

.  Given information.

The equation is:$18-2x=-36$

.  Solve the equation by 1st method.

First solve by adding 2x to each side,

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

So,$x=27$

.  Solve the equation using 2nd method.

Second, solve by subtracting 18 from each side

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

So, $x=27$

.  Conclusion.

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.