七下数学作业本（2）[绿色的那本] 一道数学题目！！
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1.\u2460\u2462\u2463
2.\uff081\uff09\u22601/2\uff082\uff09\uff1d3
3.\uff081\uff096a^2 (2)a-2
4.(1)(x-3y)/(2x+10y) \uff082\uff09-\uff082t-6h)/(5t-3h)
5.(1)-2/m (2)(m-2)/m
6.(1)(15y-2x)/5xy (2)n-3m
7.\uff081\uff09x\uff1d3 \uff082\uff09x\uff1d7/3
8.V\uff1dUS/(R+S)
9.\uff081\uff09b^2/\uff08a-b) (2)\u539f\u5f0f\uff1dxy^2.2
10.\u65e0\u89e3
11.\u8bbe\u8f6e\u8239\u5728\u9759\u6c34\u4e2d\u7684\u901f\u5ea6\u4e3av\u5343\u7c73/\u65f6\uff0c\u521921/(v-4)=[22/(v+4)]*1.5,\u89e3\u5f97v=18
12.\u8bbe\u5ba2\u8f66\u539f\u6765\u7684\u54c1\u5747\u901f\u5ea6\u662fx\u5343\u7c73/\u65f6\uff0c\u5219360/x-[360/\uff081+50%)x]=2,\u89e3\u5f97x=60
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1.\uff081\uff09D \uff082\uff09B
2.\uff081\uff095(x+2)(x-2) (2)m(a+b-c) (3)(8-a)^2 (4)(x-y)(2+a)
3.(1)(0.7x+0.2y)(0.7x-0.2y) (2)-((2ab-a)^2 (3)-3ax(a+2x)(a-2x)
(4)mx(m-n)^2
4.\uff081\uff09\u03c0R^2-4\u03c0r^2 \uff082\uff09\u03c0(R+2R)(R-2r)\u2248176\uff08\u5e73\u65b9\u5398\u7c73\uff09
5.\uff081\uff09(m-n)^2(m+n) (2)1/2ab(a+2b)^2
6.(1)2x+5y (2)2\uff08x-1/2)=2x-1
7.(1)x1=0,x2=3/2 (2)y1=-1,y2=-5
8.\u5316\u7b80\u539f\u4ee3\u6570\u5f0f\u5f97-2ab(a+b). -10
9.3a^2+7ab+2b^2=(3a+b)(a+2b).\u62fc\u6cd5\u7565
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1.x=10y+8\uff0cx=12y-2\uff0cx=48\uff0cy=4\uff0c\u8be5\u5b66\u751f\u670948\u4eba\uff0c\u5171\u79df4\u8f86\u8f66\u3002
2.\uff081\uff09\u628at=0c\u00b0\uff0cv=100\uff0ct=10c\u00b0\uff0cv=103.5\u5347\uff0c\u4ee3\u5165v=pt+q\u3002100=op+q\u2460\uff0c103.5=10p+q\u2461\u3002\u7531\u2460\u5f97\uff0cq=100-0 \u2462 \u6240\u4ee5q=100\uff0c\u7531\u2461\u5f97\uff0cq=103.5-10p \u2463\u3002\u628aq=100\u4ee3\u5165\u2461\u5f97\uff0cp=0.35.
3.\u8bbe\u7532\u4e3ax\uff0c\u4e59\u4e3ay\u3002 0.5x+0.7=35 \u2460\uff0cx+0.4=40\u2461\u3002\u628a \u2460\u4e582-\u2461\u5f97\uff0cy=30.\u628ay=30\u4ee3\u5165 \u2460\u4e2d\uff0c0.5x=14\uff0cx=18.
4.\u8db3\u7403200\u4eba\uff0c\u7bee\u7403150\u4eba\u3002
5.\u8bbe\u603b\u6536\u5165\u4e3ax\u652f\u51fa\u4e3ay\u5143\u3002\uff081+\u767e\u5206\u4e4b20\uff09x-(1-\u767e\u5206\u4e4b10\uff09=12000+11400 \u2460\uff0cx-y=12000 \u2461\u3002\u628a\u2460\u4e5810-\u2461\u4e589\u5f97x=42000\uff0cy=30000.
.
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b=(4-2x)/y
将 x=1,y=-3 带入得 a=6 b=-2/3
把x和y往里面代不就行了
将x=1，y=—3带入方程组可得a=-46，b=2/3
根据题意：x y是方程的解。
代入原方程可得：
a+1\3*(-3)=5 得a=46/9
2*1+b*(-3)=4 得b=-2/3
楼上几个居然代入方程后解都解错了~一坨汗
6、a=-46，b=-2/3
x=1,y=-3带入（1）式得a-1/3=5得a=五又三分之一
带入（2）式得2-b=4得b=-2
绛旓細b=(4-2x)/y 灏 x=1,y=-3 甯﹀叆寰 a=6 b=-2/3
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绛旓細x(y+3)(y-3) 浜哄瓧褰㈠眿椤 BC=EF Y=(5-2X)/3 X=1,Y=1鍜孹=-2,Y=3 60掳 -b^3 1/9 x=2锛寉=3 x=7 3/锛坅-2锛
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