(a²+a)(a²+a-3)-4
=(a²+a-3+3) (a²+a-3)-4
=(a²+a-3)的平方+3(a²+a-3)-4
=(a²+a-3+4) (a²+a-3-1)
=(a²+a+1) (a²+a-4)
(x-3y)²-x+3y-12
=(x-3y)²-(x-3y)-12
=(x-3y-4)×(x-3y+3)
(a²+a)(a²+a-3)-4
=(a²+a-3+3) (a²+a-3)-4
=(a²+a-3)的平方+3(a²+a-3)-4
=(a²+a-3+4) (a²+a-3-1)
=(a²+a+1) (a²+a-4)
(x-3y)²-x+3y-12
=(x-3y)²-(x-3y)-12
=(x-3y-4)×(x-3y+3)