
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
Given the universal set $U=R$, sets $A={x|1\leqslant x < 5}$, $B={x|2 < x < 8}$, $C={x|-a < x\leqslant a+3}$,
(1) Find $A∪B$, $(∁_{U}A)∩B$;
(2) If $C∩A=C$, find the range of values for $a$.

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