bài 1:
$a,$ $\frac{2}{5}xy$ $(x²y-5x+10y)$
$=$ $\frac{2}{5}$ $x³y²-2x²y+4xy²$
$b,(x²-1)(x²+2x)$
$=x^4+2x³-x²-2x$
$c,(2x-1)(3x+2)(3-x)$
$=[(2x-1)(3x+2)](3-x)$
$=(6x²+4x-3x-2)(3-x)$
$=(6x²+x-2)(3-x)$
$=18x²-6x³+3x-x²-6+2x$
$=17x²-6x³+5x-6$
$=-6x³+17x²+5x-6$
bài 2:
$a,2xy-10x²y+6xy²$
$=2xy(1-5x+3y)$
$b,25x²-9y²$
$=(5x)²-(3y)²$
$=(5x-3y).(5x+3y)$
$c,x²+y²-1-2xy$
$=(x²-2xy+y²)-1$
$=(x-y)²-1$
$=(x-y)²-1²$
$=(x-y-1).(x-y+1)$
chúc bn học tốt
Nếu được thì mk xin trả lời hay nhất nhé!^^
