
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]


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A mobile communication company offers two types of services: "Global Call" users pay a monthly rental fee of 50 yuan first, and then 0.4 yuan per minute for calls; "China Mobile" users do not pay a monthly rental fee, and pay 0.6 yuan per minute for calls (referring to local calls). If the call duration in a month is $x$ minutes, the costs for the two types of communication services are $y_1$ yuan and $y_2$ yuan, respectively.  
(1) Write the relationship between $y_1$, $y_2$, and $x$?  
(2) How many minutes of calls in a month will make the costs of the two communication methods the same?  
(3) Within what range of communication time is the "Global Call" method cheaper?

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