459÷357,余数=102
357÷102,余数=51
102÷51=2,整除
所以最大公约数=51
f(x)=(7x^5+6x^4+5x^3+4x^2+3x+2)x+8
=((7x^4+6x^3+5x^2+4x+3)x+2)x+8
=(((7x^3+6x^2+5x+4)x+3)x+2)x+8
=((((7x^2+6x+5)x+4)x+3)x+2)x+8
=(((((7x+6)x+5)x+4)x+3)x+2)x+8
x=2
f(x)=((((20+5)x+4)x+3)x+2)x+8
=(((50+4)x+3)x+2)x+8
=((108+3)x+2)x+8
=(222+2)x+8
=448+8
=456