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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)
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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