
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
In an experiment, Xiaoming fixed the upper end of a spring and hung an object at its lower end. The table below shows the corresponding values of the length $y$ of the spring and the mass $x$ of the hanging object:<br/>

| Mass of Hanging Object $x/kg$ | $0$ | $1$ | $2$ | $3$ | $4$ | $5$ |
|-------------------------------|-----|-----|-----|-----|-----|-----|
| Length of Spring $y/cm$       | $18$| $20$| $22$| $24$| $26$| $28$|

$(1)$ The table above reflects the relationship between two variables. Which one is the independent variable and which one is the dependent variable?<br/>
$(2)$ Write down the relationship between the length of the spring $y$ (in cm) and the mass of the hanging object $x$ (in kg).<br/>
$(3)$ If the length of the spring is $30$ cm, what is the mass of the hanging object at this time? (within the allowable range of the spring)

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