急!!初二上300道数学题,越短越好,最好是计算题,谢了,很急很急!!!!!!
答案:4 悬赏:60 手机版
解决时间 2021-02-11 22:16
- 提问者网友:藍了天白赴美
- 2021-02-11 00:01
急!!初二上300道数学题,越短越好,最好是计算题,谢了,很急很急!!!!!!
最佳答案
- 五星知识达人网友:迷人又混蛋
- 2021-02-11 01:13
(1)4a^3-(4a^3b^2)
=4a^3(1-b^2)
=4a^2(1+b(1-b)
(2)9x^2y^3-12xy^4+15xy^5
=3xy^3(3x-4y+5y^2)
(3)4(x-y)^3+(y^2)(y-x)^3
=4(x-y)^3-y^2(x-y)^3
=(x-y)^3(4-y^2)
=(x-y)^3(2-y)(2+y)
(4)(a+b)(a-b)-2b(3a-5b)
=a^2-b^2-6ab+10b^2
=a^2-6ab+9b^2
=(a-3b)^2
(5)(a-b)(3a+b)^2+(a+3b)^2(b-a)
=(a-b)(3a+b)^2-(a+3b)^2(a-b)
=(a-b)[(3a+b)^2-(a+3b)^2]
=(a-b)[(3a+b)+(a+3b)][(3a+b)-(a+3b)]
=(a-b)(4a+4b)(2a-2b)
=8(a+b)(a-b)^2
(6)(2x^2+1)^2-4(x^2+2x)^2
=(2x^2+1)^2-[2(x^2+2x)]^2
=(2x^2+1)^2-(2x^2+4x)^2
=[(2x^2+1)+(2x^2+4x)][(2x^2+1)-(2x^2+4x)]
=(4x^2+4x+1)(1-4x)
=(2x+1)^2(1-4x)
(7)(a+b)^2-2(a^2-b^2)+(a-b)^2
=[(a+b)^2-(a^2-b^2)]-[(a^2-b^2)-(a-b)^2]
=[(a+b)^2-(a+b)(a-b)]-[(a+b)(a-b)-(a-b)^2]
=(a+b)(a+b-a+b)-(a-b)(a+b-a+b)
=2b(a+b)-2b(a-b)
=2b(a+b-a+b)
=4b^2
(8)a^2-2ab+b^2-a+b
=(a-b)^2-(a-b)
=(a-b)(a-b-1)
=4a^3(1-b^2)
=4a^2(1+b(1-b)
(2)9x^2y^3-12xy^4+15xy^5
=3xy^3(3x-4y+5y^2)
(3)4(x-y)^3+(y^2)(y-x)^3
=4(x-y)^3-y^2(x-y)^3
=(x-y)^3(4-y^2)
=(x-y)^3(2-y)(2+y)
(4)(a+b)(a-b)-2b(3a-5b)
=a^2-b^2-6ab+10b^2
=a^2-6ab+9b^2
=(a-3b)^2
(5)(a-b)(3a+b)^2+(a+3b)^2(b-a)
=(a-b)(3a+b)^2-(a+3b)^2(a-b)
=(a-b)[(3a+b)^2-(a+3b)^2]
=(a-b)[(3a+b)+(a+3b)][(3a+b)-(a+3b)]
=(a-b)(4a+4b)(2a-2b)
=8(a+b)(a-b)^2
(6)(2x^2+1)^2-4(x^2+2x)^2
=(2x^2+1)^2-[2(x^2+2x)]^2
=(2x^2+1)^2-(2x^2+4x)^2
=[(2x^2+1)+(2x^2+4x)][(2x^2+1)-(2x^2+4x)]
=(4x^2+4x+1)(1-4x)
=(2x+1)^2(1-4x)
(7)(a+b)^2-2(a^2-b^2)+(a-b)^2
=[(a+b)^2-(a^2-b^2)]-[(a^2-b^2)-(a-b)^2]
=[(a+b)^2-(a+b)(a-b)]-[(a+b)(a-b)-(a-b)^2]
=(a+b)(a+b-a+b)-(a-b)(a+b-a+b)
=2b(a+b)-2b(a-b)
=2b(a+b-a+b)
=4b^2
(8)a^2-2ab+b^2-a+b
=(a-b)^2-(a-b)
=(a-b)(a-b-1)
全部回答
- 1楼网友:毛毛
- 2021-02-11 03:50
1+1=?
- 2楼网友:归鹤鸣
- 2021-02-11 03:06
log2(12)-log4(9)=log2(12)-log2(3^2)/log2(2^2)=log2(12)-log2(3)=log2(12/3)=log2(4)=2 {()内为真数}
- 3楼网友:有你哪都是故乡
- 2021-02-11 02:17
x(x+5)>3x2+7
x-4 < 2x+1
3x+14 > 4(2x-9)
3x-7≥4x-4
2x-3x-3<6
0.4(x-1)≥0.3-0.9x
x-4 < 2x+1
2x-6 < x-2
3×10x<500
7(X+3)>98
2x-3x+3<6
2x-3x+1<6
2x-3x+3<1
2x-19<7x+31
3x-2(9-x)>3(7+2x)-(11-6x)
2(3x-1)-3(4x+5)≤x-4(x-7)
2(x-1)-x>3(x-1)-3x-5
15-(7+5x)≤2x+(5-3x)
2X+3>0
-3X+5>0
5X+6<3X
4(2X-3)>5(X+2)
2X+4<0
5X-2≥3(X+1)
2(X-3)≤4
5m-3>0
2x-3(x-1) > 6
6x-3(x-1) ≤12-2(x+2)
3(1-3x) < 4(x-1)
8-7x+1 > 2(3x-2)
3x+14 > 4(2x-9)
3-3m<-2m
5x+3x>2
-3y+9<7
(3+8)x>6
5-3/1 x>5
11x-5x>3
-3a-9a>11
-4a+9>6
33x+33<1
5b-9<9b
6x+8>3x+8
3x-7≥4x-42x-19<7x+31.
3x-2(9-x)>3(7+2x)-(11-6x).
2(3x-1)-3(4x+5)≤x-4(x-7).
2(x-1)-x>3(x-1)-3x-5.
3[y-2(y-7)]≤4y.
15-(7+5x)≤2x+(5-3x).
3*10x<500
3*10(x+1)>500
7(x+3)>98
7x<98
2X+3>0
-3X+5>0
2X<-1
X+2>0
5X+6<3X
8-7X>4-5X
2(1+X)>3(X-7)
4(2X-3)>5(X+2)
2X<4
X+3>0
1-X>0
X+2<0
5+2X>3
X+2<8
2X+4<0
1/2(X+8)-2>0
5X-2≥3(X+1)
1/2X+1>3/2X-3
1+1/2X>2
2(X-3)≤4
5x-1>12
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