1.似乎不可分解
2.=(x-3y)(x-5y)+2(x-3y)=(x-3y)(x-5y+2)
3.=(a-b)^2+4(a-b)+3=(a-b+1)(a-b+3)
4.1/2(2a^2+2b^2+2c^2-2ab-2bc-2ac)=1/2[(a-b)^2+(a-c)^2+(b-c)^2]=0
a-b=0
b-c=0
a-c=0
a=b=c
1.似乎不可分解
2.=(x-3y)(x-5y)+2(x-3y)=(x-3y)(x-5y+2)
3.=(a-b)^2+4(a-b)+3=(a-b+1)(a-b+3)
4.1/2(2a^2+2b^2+2c^2-2ab-2bc-2ac)=1/2[(a-b)^2+(a-c)^2+(b-c)^2]=0
a-b=0
b-c=0
a-c=0
a=b=c