1.(a-b)^2+4ab-c^2
1个回答

1.(a-b)^2+4ab-c^2

=a^2-2ab+b^2+4ab-c^2

=(a+b)^2-c^2

=(a+b+c)(a+b-c)

2.a^3c-4a^2bc+4b^2c

=c(a^3-4a^2b+4b^2)

3.x^2+4y^2-4xy-1

=(x-2y)^2-1

=(x-2y+1)(x-2y-1)

4.x^2+2x-y^2-1 ,(应该是:+1吧?)

x^2+2x-y^2+1

=(x+1)^2-y^2

=(x+1+y)(x+1-y)

5.ab-1-a+b

=(ab-a)-(1-b)

=a(b-1)+(b-1)

=(b-1)(a+1)

6.a^3c-4a^2bc+4b^2c

=c(a^3-4a^2b+4b^2)

7.2x^2y-(xy-3y)

=2x^2y-xy+3y

=y(2x^2-x+3)