表达式12: "f" left parenthesis, "x" , right parenthesis equals left parenthesis, negative 2 thirds "x" plus 20 , right parenthesis left brace, 0 less than "x" less than 30 , right bracefx=−23x+200<x<30
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表达式13: min left parenthesis, "a" , 0 , right parenthesis less than "x" less than max left parenthesis, "a" , 0 , right parenthesis left brace, 0 less than or equal to "y" less than or equal to "f" left parenthesis, "a" , right parenthesis , right bracemina,0<x<maxa,00≤y≤fa
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表达式14: "x" equals 0 left brace, 0 less than "y" less than 20 , right bracex=00<y<20
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表达式15: "y" equals 20 left brace, 0 less than "x" less than 30 , right bracey=200<x<30
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表达式16: "x" equals 30 left brace, 0 less than "y" less than 20 , right bracex=300<y<20
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表达式17: left parenthesis, "x" minus 15 , right parenthesis squared plus left parenthesis, "y" minus 15 , right parenthesis squared less than or equal to 10x−152+y−152≤10
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表达式18: "x" equals 20 left brace, 10 less than "y" less than 20 , right bracex=2010<y<20
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表达式19: 20 greater than "y" greater than 10 left brace, 20 less than "x" less than 30 , right brace20>y>1020<x<30
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表达式20: 20 greater than "y" greater than 10 left brace, 20 less than "x" less than 30 , right brace20>y>1020<x<30
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表达式21: 20 greater than "y" greater than 10 left brace, 20 less than "x" less than 30 , right brace20>y>1020<x<30
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表达式22: left parenthesis, "x" minus 27.5 , right parenthesis squared plus left parenthesis, "y" minus 7.5 , right parenthesis squared less than or equal to 2.5 squaredx−27.52+y−7.52≤2.52
