h（x）=g（x）-2-ax
6
6________
______
a
1
6b
jt
c
b
a=21n1o1b=1n1o2c=1o4-1abcaba3b
12b
b6
6c
f（x）=1n（1+x）-（1+2x）+1b-c=f（oo2）f（oo2）f（o）f（o）=ob-coa-cc