Exercise 1: A 25% CPU + 1GB Memory Limit, and Verifying It — Possible Solution
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[Service] section additions:

CPUQuota=25%
MemoryMax=1G

Command to confirm the memory limit took effect:

systemctl show myapp -p MemoryMax

Explanation:

This follows the chapter's own exact syntax pattern, with the
percentage and memory value substituted for the exercise's own
specific requirements -- CPUQuota=25% instead of the chapter's own
50% example, and MemoryMax=1G instead of 512M, using G directly per
systemd's own unit-suffix convention shown in the chapter (M for
megabytes, applied the same way for gigabytes). CPUQuota=25% caps
this service to at most a quarter of a single CPU core's worth of
processing time, kernel-enforced, exactly the chapter's own stated
behavior just at a different percentage. MemoryMax=1G sets a hard 1GB
ceiling that triggers the cgroup-scoped OOM killer specifically
against this service if exceeded.

The verification command reuses the chapter's own exact syntax
(systemctl show UNIT -p PROPERTY), substituting myapp as the unit name
and MemoryMax as the specific property being checked, since the
exercise specifically asks to confirm the MEMORY limit rather than the
CPU one. Per the chapter's own daemon-reload gotcha, this command
should be run only AFTER systemctl daemon-reload and a restart of the
service, otherwise it would report the old, pre-edit configuration
rather than the newly applied limit.

WHY THIS WORKS AS AN ANSWER
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This provides both requested settings using the chapter's own correct
syntax and unit suffixes, and uses the chapter's own exact
verification command pattern targeted at the specific property
(MemoryMax) the exercise asks about.