Toán Lớp 8: 1.(x+y).(x^2+2xy+y^2)
2.(x-y).(x^2-2xy+y^2)
3.(x+y).(x-xy+y^2)
4.(x-y).(x^2+xy+y^2)
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Toán Lớp 8: 1.(x+y).(x^2+2xy+y^2)
2.(x-y).(x^2-2xy+y^2)
3.(x+y).(x-xy+y^2)
4.(x-y).(x^2+xy+y^2)
Comments ( 1 )
1)\left( {x + y} \right)\left( {{x^2} + 2xy + {y^2}} \right)\\
= \left( {x + y} \right){\left( {x + y} \right)^2}\\
= {\left( {x + y} \right)^3}\\
= {x^3} + 3{x^2}y + 3x{y^2} + {y^3}\\
2)\left( {x – y} \right)\left( {{x^2} – 2xy + {y^2}} \right)\\
= \left( {x – y} \right).{\left( {x – y} \right)^2}\\
= {\left( {x – y} \right)^3}\\
= {x^3} – 3{x^2}y + 3x{y^2} – {y^3}\\
3)\left( {x + y} \right)\left( {{x^2} – xy + {y^2}} \right)\\
= {x^3} + {y^3}\\
4)\left( {x – y} \right)\left( {{x^2} + xy + {y^2}} \right)\\
= {x^3} – {y^3}
\end{array}$