運算式 12: "d" equals StartRoot, left parenthesis, "b" Subscript, 1 , Baseline minus "a" Subscript, 1 , Baseline , right parenthesis squared plus left parenthesis, "b" Subscript, 2 , Baseline minus "a" Subscript, 2 , Baseline , right parenthesis squared , EndRootd=b1−a12+b2−a22