Here's a start.
Get Schedule Service Process ID
wmic service where name='schedule' get ProcessId ProcessId 288
Get the process that is the identifier of the parent Schedule process
wmic process where ParentProcessId=288
Edited
I don't think that at Microsoft, system tasks are what you are looking for:
The task object allows you to manage groups of processes as a whole. Job objects are potential, protected, compatible objects that manage the attributes of their associated processes. Operations performed on the task object affect all processes associated with the task object. Examples include enforced restrictions, such as the size of the working set and the priority of a process, or the termination of all processes associated with a job.
I think you are looking for a process.
To answer your question, I am looking for processes launched by the schedule service. If you want an exact location, it is set by the ExecutablePath property.
wmic process where ParentProcessId=288 get ExecutablePath ExecutablePath C:\Windows\system32\wuauclt.exe
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