Nhân hết ra giúp mình ạ ` (x+y+z)^3 = ?` 04/09/2021 Bởi Abigail Nhân hết ra giúp mình ạ ` (x+y+z)^3 = ?`
Đáp án: $\text{ (x+y+z)³ }$ $\text{= [(x+y+z)(x+y+z)] (x+y+z) }$ $\text{ = [ x² +xy +xz+xy+y²+zy+xz+zy+z² ] (x+y+z) }$ $\text{ = [x²+2xy+2xz+2zy+y²+z²] (x+y+z) }$ $\text{ = x³+x²y+x²z+2x²y+2xy²+2xyz+2x²z+2xyz +2xz² +2xyz+2zy²+2z²y+xy²+y³ +zy²+xz²+zy²+z³ }$ $\text{ = x³+3x²y +3x²z+3xy²+6xyz+3xz²+y³+3y²z+3yz²+z³ }$ Bình luận
Đáp án:
Giải thích các bước giải:
Đáp án:
$\text{ (x+y+z)³ }$
$\text{= [(x+y+z)(x+y+z)] (x+y+z) }$
$\text{ = [ x² +xy +xz+xy+y²+zy+xz+zy+z² ] (x+y+z) }$
$\text{ = [x²+2xy+2xz+2zy+y²+z²] (x+y+z) }$
$\text{ = x³+x²y+x²z+2x²y+2xy²+2xyz+2x²z+2xyz +2xz² +2xyz+2zy²+2z²y+xy²+y³ +zy²+xz²+zy²+z³ }$
$\text{ = x³+3x²y +3x²z+3xy²+6xyz+3xz²+y³+3y²z+3yz²+z³ }$