Question

因式分解；a的2次方-4ab+3b的2次方+2bc-c的2次方 2. x的2次方-6xy+9y的2次方-10x+30y+25

Answer 1

1、a^2-4ab+3b^2+2bc-c^2
=(a^2-4ab+4b^2)-(b^2-2bc+c^2)
=(a-2b)^2-(b-c)^2
=[(a-2b)-(b-c)]*[(a-2b)+(b-c)]
=(a-3b+c)(a-b-c)
2、x^2-6xy+9y^2-10x+30y+25
=(x-3y)^-10(x-3y)+25................(把（x-3y）看做整体)
=[(x-3y)-5]^2=(x-3y-5)^2

Answer 2

a的2次方-4ab+3b的2次方+2bc-c的2次方
=(a-3b)(a-b)+2bc-c�0�5
=(a-3b+c)(a-b-c)

x的2次方-6xy+9y的2次方-10x+30y+25
=(x-3y)�0�5-10(x-3y)+25
=(x-3y-5)�0�5