Đáp án:
Giải thích các bước giải:
$\text{a) (3x-2)²+(2x+5)²-(3x+4)(3x-4)}$
$\text{= 9x²-12x+4+4x²+20x+25-9x²+16}$
$\text{= 4x²+8x+45}$
$\text{b) Sửa (3x+2)(9x²-6x+4)+(5-3x)(25+15x+9x²)-9}$
$\text{= 27x³+8+125-27x³-9}$
$\text{= 124}$
$\text{c) (x-3)³-(x+2)(x-2)(x-1)}$
$\text{=x³-9x²+27x-27-(x²+4)(x-1)}$
$\text{=x³-9x²+27x-27-x³+x²-4x+4}$
$\text{= -8x²+23x-23}$
$\text{d) (x+2y)³-(2y-x)(4x²+2xy+y²)}$
$\text{= x³ + 6x²y+12xy+8y³-8y³+x³}$
$\text{= 2x³+6x²y+12y}$
$\text{e) (x-3y)²-(2y-x)(3x+2y)(3x-2y)}$
$\text{= x²-6xy+9y²-(2y-x)(9x²-4y²)}$
$\text{= x²-6xy+9y²-18x²y+8y³+9x³+4xy²(Câu này ko biết có phải rút gọn ko)}$