Đáp án:
Giải thích các bước giải:
$3x^2-3xy-5x+5y$
$=3x.(x-y)-(5x-5y)$
$=3x.(x-y)-5.(x-y)$
$=(x-y).(3x-5)$
$b)x^2+4x-y^2+4$
$=(x^2+4x+4)-y^2$
$=(x+2)^2-y^2$
$=(x+y+2).(x-y+2)$
$c)5x^2+5xy-x-y$
$=5x.(x+y)-(x+y)$
$=(x+y).(5x-1)$
$d)27x^3-27x^2y+9xy^2-y^3$
$=(3x)^3-3.(3x)^2.y+3.3x.y^2-y^3$
$=(3x-y)^3$