数学题(多项式的乘法) 求.现在.(1)(3x+2)(x-1)-(x-1)(2x+3)(2)(2x-y)(x-2y)-2(x-y)(x+y3.先化简,再求值:x(x+2)-(x+1)(x-1)4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n.
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/16 13:25:29
数学题(多项式的乘法) 求.现在.(1)(3x+2)(x-1)-(x-1)(2x+3)(2)(2x-y)(x-2y)-2(x-y)(x+y3.先化简,再求值:x(x+2)-(x+1)(x-1)4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n.
数学题(多项式的乘法) 求.现在.
(1)(3x+2)(x-1)-(x-1)(2x+3)
(2)(2x-y)(x-2y)-2(x-y)(x+y
3.先化简,再求值:x(x+2)-(x+1)(x-1)
4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n.
数学题(多项式的乘法) 求.现在.(1)(3x+2)(x-1)-(x-1)(2x+3)(2)(2x-y)(x-2y)-2(x-y)(x+y3.先化简,再求值:x(x+2)-(x+1)(x-1)4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n.
(1)(3x+2)(x-1)-(x-1)(2x+3)
=3x^2-x-2-(2x^2+x-3)=x^2-2x+1
(2)(2x-y)(x-2y)-2(x-y)(x+y
=2x^2-5xy+2y^2-2(x^2-y^2)=-5xy+4y^2
3.x(x+2)-(x+1)(x-1)
=x^2+2x-(x^2-1)=2x+1
4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n.
(mx2+nx+4)(x-2)=m x^3+(n-2m)x^2+(4-2n)x-8
n-2m=0
4-2n=0
n=2,m=1
1)(3x+2)(x-1)-(x-1)(2x+3)
=3x^2-x-2-(2x^2+x-3)=x^2-2x+1
(2)(2x-y)(x-2y)-2(x-y)(x+y
=2x^2-5xy+2y^2-2(x^2-y^2)=-5xy+4y^2
3.x(x+2)-(x+1)(x-1)
=x^2+2x-(x^2-1)=2x+1
4.若在(mx2+nx+4)(x...
全部展开
1)(3x+2)(x-1)-(x-1)(2x+3)
=3x^2-x-2-(2x^2+x-3)=x^2-2x+1
(2)(2x-y)(x-2y)-2(x-y)(x+y
=2x^2-5xy+2y^2-2(x^2-y^2)=-5xy+4y^2
3.x(x+2)-(x+1)(x-1)
=x^2+2x-(x^2-1)=2x+1
4.若在(mx2+nx+4)(x-2)的积中不含x2项和x项,求m、n。
(mx2+nx+4)(x-2)=m 希望能帮助您
收起
1.1-2x+X2 2.4Y2-5XY 3.2x+1 4.m=1,n=-2