Nothing in life is free. Sadly, the same is true of projects. If you want to finish sooner, something has to give, whether reducing the amount of work (scope) or increasing the amount of resources (people and/or money). If you cut the size of the project team or its budget, either the finish data gets pushed out or the scope of work has to be shrink. Finally, if you want to increase the scope of work, you’ll need either more people/money or more time.
So it’s up to you. You can always adjust the deadline, resources or scope one at a time. But whenever you do so, think of the impact on the other two aspects. Interestingly, many executives don’t understand this principle, thinking it’s something sufficient carrots and sticks can overcome, yet it is a mathematical rule.
Note – some variants of the triple constraint take it further and include as ‘quality’ as a forth variable. Here I include it as part of scope.