
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 vectors $\overrightarrow {a} = (1, 2)$ and $\overrightarrow {b} = (1, -1)$.
(Ⅰ) Calculate $|2\overrightarrow {a} - \overrightarrow {b}|$.
(Ⅱ) Let vector $\overrightarrow {c} = x\overrightarrow {a} + x^{2}\overrightarrow {b}$. If the angle between $\overrightarrow {b}$ and $\overrightarrow {c}$ is obtuse, find the range of real number $x$.

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