Giải thích các bước giải:
Bài 1:
a.$27y^3-9y^2+y-\dfrac{1}{27}$
$=(3y)^3-3.(3y)^2.\dfrac 13+3.3y.(\dfrac 13)^2-(\dfrac 13)^3=(3y-\dfrac 13)^3$
b.$8x^6+12x^4y+6x^2y^2+x^3$
$=x^2(8x^4+12x^2y+6y^2+x)$
Bài 2:
$a.153^2+94.153+47^2$
$=153^2+2.47.153+47^2$
$=(47+153)^2$
$=200^2=40 000$
b.$126^2-152.126+5776$
$=126^2-2.76.126+76^2$
$=(126-76)^2=50^2=2500$
$c.3^8.5^8-(15^4-1)(15^4+1)$
$=(3.5)^8-(15^8-1)$
$=15^8-15^8+1=1$