Đáp án+Giải thích các bước giải:
Bài 1:
a) $A=x^2-x=x(x-1)$
b) $A= 5x(x-1)-(1-x)=5x(x-1)+(x-1)=(5x+1)(x-1)$
c) $A= 3x-3y=3(x-y)$
d) $A= x( y-1)-y(1-y)=x(y-1)+y(y-1)=(x+y)(y-1)$
e) $A=(x+1)^2-3(x+1)=(x+1)(x+1-3)=(x+1)(x-2)$
f) $ A=5x-20y=5(x-4y)$
g)$A= 7x(x-y)-(y-x)=(7x+1)(x-y)$
w) $A=2x(x-2)-(x-2)^2=(x-2)(2x-x+2)=(x-2)(2-x)$
h) $A=3xy^2+6xyz=3xy(y+3z)$
i) $A=z(x+y)-5(x+y)=(z-5)(x+y)$
K)$A=3x(x-1)^2-(1-x)^3=3x(1-x)^2-(1-x)^3=(1-x)^2(3x-1+x)$
$=(1-x)^2(4x-1)$
l) $A=8xy^2-2x^2y=2xy(4y-x)$
m) $A=3x(x+5)-2(5+x)=(3x-2)(x+5$
n) $A=3x(x+2)-5(x+2)^2=(x+2)(3x-5x-10)=-(x+2)(2x+10)$
bài 2:
