A rectangular frame’s perimeter is \(8.6\) feet. If its length is \(2.5\) feet, suppose we want to find how long is its width. A rectangle’s perimeter formula is


where \(P\) stands for perimeter, \(l\) for length and \(w\) for width. We can solve this problem using the equation:


Check whether \(1.8\) is a solution for \(w\) of this equation.