Bài 1:
a)
$A=(3x-5)(2x+11)-(2x+3)(3x+7)$
$=6x^2+33x-10x-55-(6x^2+14x+9x+21)$
$=-76$
b)
$B=4x(3x-2)-3x(4x+1)=12x^2-8x-(12x^2-3x)=-5x$
c)
$C=(x+3)(x-3)-(x-1)^2=(x^2-9)-(x^2-2x+1)=2x-10$
Bài 2:
a)
$x^2-y^2-2x+2y=(x^2-y^2)-(2x-2y)=(x-y)(x+y)-2(x-y)=(x-y)(x+y-2)$
b)
$x^3-5x^2+x-5=x^2(x-5)+(x-5)=(x^2+1)(x-5)$
c)
$x^2-2xy+y^2-9=(x-y)^2-3^2=(x-y-3)(x-y+3)$