
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 $U = \mathbb{R}$, let the sets $M = \{ x | -2 \leqslant x \leqslant 5 \}$, $N = \{ x | a + 1 \leqslant x \leqslant 2a + 1 \}$.  
(Ⅰ) If $a = 2$, find $M \cap (\complement_{\mathbb{R}} N)$;  
(Ⅱ) If $M \cup N = M$, find the range of the real number $a$.

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