Giải:
1) \(\left(x+y+z\right)^2\)
\(=x^2+y^2+z^2+2xy+2yz+2xz\)
2) \(\left(1-5a\right)^2\)
\(=1-10a+25a^2\)
3) \(\left(5a-4b\right)^2\)
\(=25a^2-40ab+16b^2\)
4) \(\left(a-b-c\right)^2\)
\(=a^2+b^2+c^2-2ab+2bc-2ac\)
5) \(\left(a+1\right)^3\)
\(=a^3+3a^2+3a+1\)
6) \(\left(x+2\right)^3\)
\(=x^3+6x^2+12x+8\)
7) \(\left(2x+3y\right)^3\)
\(=8x^3+3.4x^2.3y+3.9y^2.2x+27y^3\)
\(=8x^3+36x^2y+54xy^2+27y^3\)
8) \(\left(4x+2y\right)^3\)
\(=64x^3+3.16x^2.2y+3.4x.4y^2+8y^3\)
\(=64x^3+396x^2y+48xy^2+8y^3\)
9) \(\left(x-3\right)^3\)
\(=x^3-9x^2+27x-27\)
10) \(\left(4-4y^2\right)^3\)
\(=4^3-3.4^2.4y^2+3.4.\left(4y^2\right)^2-\left(4y\right)^3\)
\(=64-192y^2+192y^4-64y^3\)
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