已知-3a^m bc^2 与6a^3b^n C^2是同类项,求代数式3m^2n-【2mn^2-3(-m^2n+mn^2)】
的值
已知A=-x^2+2xy-3y^2,B=5x^2-xy+2y^2,当X=2 Y=-3时 ,求代数式2A-3B的值
化简下列各式
(3x^2-4)-(2x^2-5x+6)+(x^2-5x)
9m^2+【4m^2-3m-(2m^2-6m)】
已知-3a^m bc^2 与6a^3b^n C^2是同类项,求代数式3m^2n-【2mn^2-3(-m^2n+mn^2)】
的值
已知A=-x^2+2xy-3y^2,B=5x^2-xy+2y^2,当X=2 Y=-3时 ,求代数式2A-3B的值
化简下列各式
(3x^2-4)-(2x^2-5x+6)+(x^2-5x)
9m^2+【4m^2-3m-(2m^2-6m)】
1.由已知得m=3 n=1
∴3m^2n-[2mn^2-3(-m^2n+mn^2)]
=3m^2n-(2mn^2+3m^2n-3mn^2)
=mn^2
=3
2.2A-3B=-2x^2+4xy-6y^2-15x^2+3xy-6y^2
=-17x^2+7xy-12y^2
代入数值得
原式=-68-42-108=-218
3.(1)原式=3x^2-4-2x^2+5x-6+x^2-5x=2x^2-10
(2)原式=9m^2+4m^2-3m-2m^2+6m=11m^2+3m
1.由已知得m=3 n=1
∴3m^2n-[2mn^2-3(-m^2n+mn^2)]
=3m^2n-(2mn^2+3m^2n-3mn^2)
=mn^2
=3
2.2A-3B=-2x^2+4xy-6y^2-15x^2+3xy-6y^2
=-17x^2+7xy-12y^2
代入数值得
原式=-68-42-108=-218
3.(1)原式=3x^2-4-2x^2+5x-6+x^2-5x=2x^2-10
(2)原式=9m^2+4m^2-3m-2m^2+6m=11m^2+3m
1.由已知得m=3 n=1
∴3m^2n-[2mn^2-3(-m^2n+mn^2)]
=3m^2n-(2mn^2+3m^2n-3mn^2)
=mn^2
=3
2.2A-3B=-2x^2+4xy-6y^2-15x^2+3xy-6y^2
=-17x^2+7xy-12y^2
代入数值得
原式=-68-42-108=-218
3.(1)原式=3x^2-4-2x^2+5x-6+x^2-5x=2x^2-10
(2)原式=9m^2+4m^2-3m-2m^2+6m=11m^2+3m
1.由已知得m=3 n=1
∴3m^2n-[2mn^2-3(-m^2n+mn^2)]
=3m^2n-(2mn^2+3m^2n-3mn^2)
=mn^2
=3
2.2A-3B=-2x^2+4xy-6y^2-15x^2+3xy-6y^2
=-17x^2+7xy-12y^2
代入数值得
原式=-68-42-108=-218
3.(1)原式=3x^2-4-2x^2+5x-6+x^2-5x=2x^2-10
(2)原式=9m^2+4m^2-3m-2m^2+6m=11m^2+3m