A rectangular frame’s perimeter is \(6.8\) feet. If its length is \(2.3\) 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 \(4.5\) is a solution for \(w\) of this equation.