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请教几道计算题 1.(-2a+3b-c)的平方=2.(-3x+2y-z)(3x+2y+z)=3.(3x-2)的立方=4.

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/04/29 11:58:02
请教几道计算题
1.(-2a+3b-c)的平方=
2.(-3x+2y-z)(3x+2y+z)=
3.(3x-2)的立方=
4.(-2m-3n)的平方(2m-3n)的平方=
1.(-2a+3b-c)^2
=(3b-(2a+c))^2
=9b^2-6b(2a+c)+(2a+c)^2
=9b^2-12ab-6bc+4a^2+4ac+c^2
=4a^2+9b^2+c^2-12ab-6bc+4ac
2.(-3x+2y-z)(3x+2y+z)
=(2y-(3x+z))(2y+(3x+z))
=4y^2-(3x+z)^2
=4y^2-9x^2-6xz-z^2
=4y^2-9x^2-z^2-6xz
3.(3x-2)^3
=(3x)^3-6(3x)^2-3(3x)*2^2-2^3
=9x^3-54x^2-108x-8
4.(-2m-3n)^2(2m-3n)^2
=(2m+3n)^2(2m-3n)^2
=((2m)^2-(3n)^2)^2
=(4m^2-9n^2)^2
=(4m^2)^2-2*(4m^2)*(9n^2)+(9n^2)^2
=16m^4-72*m^2*n^2+81n^4