[No.Name]

ลองทำแบบของผมบ้างนะครับ

$p^2-2p+1=3$

$1-8p+4p^2-2p^3-2p^4+3p^5+2p^6-p^7=-(p^7-2p^6+p^5)+4p^5-2p^4-2p^3+4p^2-8p+1$

$=-3p^5+4p^5-2p^4-2p^3+4p^2-8p+1=p^5-2p^4-2p^3+4p^2-8p+1$

$=(p^5-2p^4+p^3)-3p^3+4p^2+8p+1$

$=3p^3-3p^3+4p^2+8p+1$

$=4(p^2-2p+1)-3$

$=12-3$

$=9$