
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 the diagram, $PQR$ is a straight line, and point $S$ is connected to $Q$ and $R$. Additionally, $T$ is another point not on line $PQR$, creating triangle $QST$. Given $\angle PQS = 120^\circ$, $\angle QRS = 50^\circ$, and $\angle QST = 30^\circ$, what is the value of $x$, where $x$ is the measure of $\angle QSR$?

[asy]
draw((-2,0)--(8,0),linewidth(0.7)); 
draw((8,0)--(5,-5.5)--(0,0),linewidth(0.7));
draw((5,-5.5)--(2,2),linewidth(0.7)); // Triangle QST
label("$P$",(-2,0),W); label("$Q$",(0,0),N); label("$R$",(8,0),E); 
label("$S$",(5,-5.5),S); label("$T$",(2,2),N);

label("$120^\circ$",(0,0),NW); label("$50^\circ$",(7,0),S);
label("$30^\circ$",(2,1),NE);

label("$x^\circ$",(5,-4.5));

[/asy]

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