
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
(2016 Autumn • Yuecheng District School Midterm) Let set $A=\{a_1, a_2, a_3, a_4\}$. If the set $B=\{-1, 3, 5, 8\}$ is composed of the sums of the elements of all three-element subsets of $A$, then find the set $A$.

Present the answer in LaTex format: \boxed{Your answer}
user