a,\(x^3-3x^2+3x-1-y^3=\left(x^3-1\right)-\left(3x^2-3x\right)-y^3\)
\(=\left(x-1\right)\left(x^2+x+1\right)-3x\left(x-1\right)-y^3\)
\(=\left(x-1\right)\left(x^2-2x+1\right)-y^3\)
\(=\left(x-1\right)^3-y^3=\left(x-1-y\right)\left[\left(x-1\right)^2+y\left(x-1\right)+y^2\right]\)
....
\(8x^2+10x-3\)
\(=8x^2+12x-2x-3\)
\(=4x.\left(2x+3\right)-\left(2x+3\right)\)
\(=\left(4x-1\right).\left(2x+3\right)\)
\(x^3-3x^2+3x-1-y^3\)
\(=\left(x-1\right)^3-y^3\)
\(=\left(x-1-y\right)\left(x-1\right)^2+\left(x-1\right).y+y^2\)
ps: lớp 7, ko chắc
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câu a ấy quên cái ngoặc nhoa :<
\(=\left(x-1-y\right).\left[\left(x-1\right)^2+\left(x-1\right).y+y^2\right]\)