"The length of a rectangle is 4cm more than the width. If the length were to be decreased by 5cm and the width decreased by 2cm, the perimeter would be 18cm. Calculate the dimensions of the rectangle."

I don't understand where to start with this question. I suck at problem solving questions, so a detailed explaintion for this question will be very much appreciated. Thank you.

\[

\text{Let the width of the rectangle be }x\\

\therefore \text{the width}=x\text{ and the length}=x+4\\

\text{If we decrease the length by 5 and decrease the width by 2, then}\\

\text{width}=x-2,\,\text{length}=x+4-5=x-1\\

\begin{aligned}\\

\text{Perimeter}=2(x-2)+2(x-1)&=18\\

4x-6&=18\\

x&=6\\

\end{aligned}\\

\therefore \text{ the dimensions of the original rectangle are: } 6cm\times10cm\\

\]

Edit: fixing my latex