X的平方*(Y的平方-1)+2X(Y的平方-1)+(Y的平方-1)
=(Y^2-1)(X^2+2X+1)
=(Y^2-1)(X+1)^2
=(Y+1)(Y-1)(X+1)^2
(C+D)的平方-4(C+D-1)
=(C+D)^2-4(C+D)+4
=(C+D+2)^2
X平方-8X+7
=(X-1)(X-7)
( X平方+3X+1)的平方-1
=(X^+3X+1+1)(X^2+3X+1-1)
=(X^2+3X+2)(X^2+3X)
=(X+1)(X+2)X(X+3)
=X(X+1)(X+2)(X+3)
X平方-4XY+4Y的平方+5X-10Y+6
=(X-2Y)^2+5(X-2Y)+6
(X-2Y+2)(X-2Y+3)