How do I subtract days from a date/time field using GlideDateTime in Workflow when task is created?

[vampyre82nd]

I have a requirement to create 21 tasks for different teams, I am using a workflow for this. These tasks all have to be completed at different times, before a set end date. I have read through all the different posting here and have tried most of them to no avail. Is it possible to use a GDT script in the create task script area to subtract days from the u_release_end_date field and then populate the u_release_plan_end field? Or does this have to be done in a business rule?

task.u_release_end_date = current.work_end;

var gdt = current.u_release_end_date.getGlideObject();
gdt.addDays(-2);
task.u_release_plan_end = gdt;

[Mike Patel]

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