表达式6: "X" equals left parenthesis, "a" , "f" left parenthesis, "a" , right parenthesis , right parenthesisX=a,fa
6
表达式7: "t" Subscript, "g" , Baseline left parenthesis, "x" , right parenthesis equals "f" prime left parenthesis, "a" , right parenthesis left parenthesis, "x" minus "a" , right parenthesis plus "f" left parenthesis, "a" , right parenthesistgx=f′ax−a+fa