Bài 5
$a,(2x-1)(8x-3)-(4x+1)²$
$=2x(8x-3)-1(8x-3)-[(4x)²+2.4x.1+1²]$
$=16x²-6x-8x+3-16x²-8x-1$
$=2-22x$
$=2(1-11x)$
$b,(4x²-1):(2x+1)$
$=(2x-1)(2x+1):(2x+1)$
$=2x-1$
$c,(x²-6x+9):(x-3)$
$=(x-3)²:(x-3)$
$=x-3$
$d,(12x²y²-6x³y²):3x²y-4y(2x-5)$
$=4y-2xy-8xy+20y$
$=24y-10xy$
$=2y(12-5x)$