I like to use the warm-up time to challenge students sometimes with very complex or complicated problems. Students are allowed to work together within their cooperative groups to complete the given task. Since the activity today centers around the mechanics of solving equations, I would recommend a complex algebraic equation as a lesson opening question. Below is an example of a complex equation that could be used as a good lesson opener and then ask someone or a few someones to go to the board to walk the class through a solution. If a student says he/she can't finish the equation but can work a step or two to generate a better equivalent equation then great, ask him/her to demonstrate as much as possible. You will need to move about the room providing feedback as students work because they will have questions. This is a great example of practice harder than you play (practice harder than you will be tested).
Solve for x: 4 - 2 (6x – 5) = 2x + 1
You will not need a whole group wrap up session for this activity since the students are expected to check their work and discuss as they finish. Therefore, the wrap up time is really time to assign homework and further the practice of solving equations. The homework image is an example of problems you could assign and I generated these problems by vising the website http://www.math.com/students/worksheet/algebra_sp.htm. I like this website because I can customize the problems and it generates an answer key which I post online for students to use to check their work as they completed the homework. I chose 2 two-step equations and then five each of distributive property, combining like terms, and variables on both sides. I also selected 20% of the coefficients as fractions.