设f(x)=ax+b
f(x+1)=a(x+1)+b
f(x-1)=a(x-1)+b
3f（x+1）-2f（x-1）=3a(x+1)+3b-[2a(x-1)+2b]
=ax+5a-b=2x+17
故a=2,5a+b=17
故a=2,b=7
f(x)=2x+7
一道简单的高中函数题 （请写明详细过程,因为我一点都不会写）
设f(x)=ax+b
f(x+1)=a(x+1)+b
f(x-1)=a(x-1)+b
3f（x+1）-2f（x-1）=3a(x+1)+3b-[2a(x-1)+2b]
=ax+5a-b=2x+17
故a=2,5a+b=17
故a=2,b=7
f(x)=2x+7