
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 two lines $l_1: 2x-y+7=0$, $l_2: x+y-1=0$, and point $A(m, n)$ is the intersection of $l_1$ and $l_2$,
(1) Find the values of $m$ and $n$;
(2) Find the equation of the line $l_3$ that passes through point $A$ and is perpendicular to line $l_1$;
(3) Find the equation of the line $l_4$ that passes through point $A$ and is parallel to the line $l: 2x-3y-1=0$.

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