The main challenge of a project manager is: how to balance between competing project constraints. Do you agree? Explain?

Yes, that's right.

Throughout the project lifecycle, all efforts/actions of PM are focussed on not letting the project to slip the deadline (Time), deliver agreed features for this project (Scope), do not let the project consume excess resources, i.e stay within the budget (Cost)...

Yes I agree.

Competing Project Constraints:

1. Schedule/ time
2. Budget/ cost
3. Scope
4. Quality
5. Resources and
6. Risk

Impact of change in constraints: If any one constraint changes, at least one other constraint is likely to be affected. For example, to shorten the schedule, you need additional resources which may lead to an increase in the cost. So, it is important for the project management team to evaluate the effect of change in one constraint on other constraints.

Importance of Constraints for Project Planning: While it may seem that constraints are difficult to handle, it is very much necessary to define a finite problem. If there are no constraints, you would be working with an indefinite problem in space. So, its always important for a project manager to understand and list down the constraints in a project. This would help him/ her to effectively plan the project. During planning, the project management team should be clear that they are able to work within all the given constraints. If it is found that the constraints cannot be met, then it has to be brought to the notice of the senior management (or) project sponsor (or) the customer.

yes I agree. but constraints in general are fundamental when modelling a project. 

Yes I agree, not having balance might results in misalignment with project objectives

Thanks for your invitation. 

I agree. 

I think that the project manager must first attend a work plan that applied in the management of his project and this plan includes resource management, risk management and schedule progress of the work and how to Exploits the most of financial and human resources and mechanisms available to him in the project, as well as quality control of materials.

Thanks Mr. Raafat for this question.

Yes I agree.

A good PM should not allow spending resources on one constraint much than it deserves if he would achieve project objectives.

AGREED................

Project Management is bout balance and compromize when 

1. Project is under- resourced (people , money, and facilities/tools)
2. Competing parallel tasks demanding the same reources which cannot be made available to all these tasks together
3. Running multiple projects (under different project managers) with no proper coordination among them
4. Unexpected developments forcing cutting down on resources during the execution of the projects

Yes that,s right

agreed

Agreed