1.求2a^2-4a 1和-3a^2 2a-5的差.2.求5(3a^2-ab^2)-4(- ab^2 3a^b)的值,其中a=2,b=3 6.已知a^2+5ab=6,3b^2+2ab=8,求代数式a^ 2+11ab 9b^2的值.3.化简(1)(x^2+5xy-y^2)-(x^2+3xy-2y^2)(2)-(2x-3y+7)+2(6x-5y-2)(3)5(x+y)-4(3x-2y)+3(2x-3y) (4)-2(8m^2
来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/23 17:09:47
1.求2a^2-4a 1和-3a^2 2a-5的差.2.求5(3a^2-ab^2)-4(- ab^2 3a^b)的值,其中a=2,b=3 6.已知a^2+5ab=6,3b^2+2ab=8,求代数式a^ 2+11ab 9b^2的值.3.化简(1)(x^2+5xy-y^2)-(x^2+3xy-2y^2)(2)-(2x-3y+7)+2(6x-5y-2)(3)5(x+y)-4(3x-2y)+3(2x-3y) (4)-2(8m^2
1.求2a^2-4a 1和-3a^2 2a-5的差.
2.求5(3a^2-ab^2)-4(- ab^2 3a^b)的值,其中a=2,b=3
6.已知a^2+5ab=6,3b^2+2ab=8,求代数式a^ 2+11ab 9b^2的值.
3.化简
(1)(x^2+5xy-y^2)-(x^2+3xy-2y^2)
(2)-(2x-3y+7)+2(6x-5y-2)
(3)5(x+y)-4(3x-2y)+3(2x-3y)
(4)-2(8m^2n^2-3m^2)-5m^2n^2-3(-3m^2n^2 2m^2)中间空格是加号
1.求2a^2-4a 1和-3a^2 2a-5的差.2.求5(3a^2-ab^2)-4(- ab^2 3a^b)的值,其中a=2,b=3 6.已知a^2+5ab=6,3b^2+2ab=8,求代数式a^ 2+11ab 9b^2的值.3.化简(1)(x^2+5xy-y^2)-(x^2+3xy-2y^2)(2)-(2x-3y+7)+2(6x-5y-2)(3)5(x+y)-4(3x-2y)+3(2x-3y) (4)-2(8m^2
求2a^2-4a 1和-3a^2 2a-5的差.
2a^2-4a+1-(-3a^2+2a-5)
=2a^2-4a+1+3a^2-2a+5
=5a^2-6a+5
2.求5(3a^2-ab^2)-4(- ab^2 3a^b)的值,其中a=2,b=3
5(3a^2-ab^2)-4(- ab^2+ 3a^2b)
=15a^2-5ab^2+4ab^2-12a^2b
=15a^2-ab^2-12a^2b
=a(15a-b^2-12ab)
当a=2 b=3时,
a(15a-b^2-12ab)
=2(15*2-9-60)
=-78
6.已知a^2+5ab=6,3b^2+2ab=8,求代数式a^ 2+11ab 9b^2的值.
a^ 2+11ab +9b^2
=a^ 2+5ab+3(3b^2+2ab)
=6+3*8
=30
3.化简
(1)(x^2+5xy-y^2)-(x^2+3xy-2y^2)
=2xy+y^2
(2)-(2x-3y+7)+2(6x-5y-2)
=10x-7y-11
(3)5(x+y)-4(3x-2y)+3(2x-3y)
=5x+5y-12x+8y+6x-9y
=-x+4y
是要答案还是要过程呢?