運算式 4: "m" times left parenthesis, "x" minus "a" , right parenthesis plus "f" left parenthesis, "a" , right parenthesism·x−a+fa
4
運算式 5: "m" equals StartFraction, "f" left parenthesis, "b" , right parenthesis minus "f" left parenthesis, "a" , right parenthesis Over "b" minus "a" , EndFractionm=fb−fab−a
