Đáp án:
Giải thích các bước giải:
$\text{a/ (2x+1)²-4(x+2)²}$
$\text{= 4x²+4x+1-4(x²+4x+4)}$
$\text{= 4x²+4x+1-4x²-16x-16}$
$\text{= -12x-15}$
$\text{b/ (x+3)²-(x-4)(x+8)}$
$\text{= x²+6x+9-x²-8x+4x+32}$
$\text{= 2x+41}$
$\text{c/ (2x+y)(4x²-2xy+y²)-(2x-y)(4x²+2xy+y²)}$
$\text{= 8x³+y³-8x³+y³}$
$\text{= 2y³}$
$\text{d/ (x-1)³-(x+3)(x²-3x+9)+3(x²-4)}$
$\text{= x³-3x²+3x-1-x³-27+3x²-12}$
$\text{= 3x - 40}$
