(X-1)X(X+1)(X+2)+1把步驟寫出來可以讓人理解就OK了,謝!

熱心網(wǎng)友

(X-1)X(X+1)(X+2)+1=[X(X+1)][(X+2)(X-1)]+1=(X^2+X)(X^2+X-2)+1=[ 設(shè): Y=X^2+X ]Y^2-2Y+1=(Y-1)^2=(X^2+X-1)^2