นิพจน์ 2: "f" Subscript, "r" , Baseline left parenthesis, "x" , right parenthesis equals 2 plus "x"frx=2+x
2
นิพจน์ 3: "f" Subscript, "l" , Baseline left parenthesis, "x" , right parenthesis less than or equal to "f" Subscript, "r" , Baseline left parenthesis, "x" , right parenthesisflx≤frx