初一下数学题~高手请进帮帮忙！！
\u521d\u4e00\u4e0b\u6570\u5b66\u98981. x-v \u7531\u5e73\u65b9\u5dee\u516c\u5f0f\u03c72\uff0d\u03bd2=(x+v)(x-v)\u5f97\u539f\u5f0f=(x+v)(x-v)\u00f7\uff08\u03c7\uff0b\u03bd\uff09 =x-v
2. -3m2n+2mn2-1/8n3 \u4f9d\u6b21\u9664\u4ee5\uff08\uff0d8m\uff09\u5373\u53ef\u3002
\u53e6\u5916\uff0cm3\u00f7m=m(3-1)=m2 m5\u00f7m2=m(5-2)=m3
3. -4v \u5148\u8ba1\u7b97\u3010\uff08\u03c7\uff0b\u03bd\uff092\uff0d\uff08\u03c7\uff0d\u03bd\uff092\u3011\u7528\u5b8c\u5168\u5e73\u65b9\u548c/\u5dee\u516c\u5f0f\u5f974xv
\u6240\u4ee5\u539f\u5f0f=\uff084xv+4\u03c7\u03bd\uff09\u00f7\uff08\uff0d2\u03c7\uff09= -4v
4. 1/2(x-v) \u5148\u63d0\u53d6\u516c\u56e0\u5f0f\uff08\u03c7\uff0d\u03bd\uff09\u5f97
\u3010\uff08\u03c7\uff0b\u03bd\uff09\uff0d\uff08\u03c7\uff0d\u03bd\uff09\u3011\uff08\u03c7\uff0d\u03bd\uff09\u00f7\uff084\u03bd\uff09=2v\uff08\u03c7\uff0d\u03bd\uff09\u00f7\uff084\u03bd\uff09=1/2(x-v)
5. 4x2+12v-10v \u957f\u65b9\u5f62\u9762\u79ef\u516c\u5f0f\uff1a\u9762\u79efS=\u957faX\u5bbdb \u6240\u4ee5\u957fa=\uff0812\u03c72\u03bd\uff0d10\u03c73)\u00f72\u03c72=6v-5x
\u957f\u65b9\u5f62\u5468\u957f\u516c\u5f0f\uff1a\u5468\u957fC=2\uff08a+b) \u6240\u4ee5\u5468\u957fC=2\uff086v-5x+2\u03c72\uff09=4x2+12v-10v
6. a=-1/2 b=3 2a+b-3 \u258fa\uff0b1/2\u258f\u22650 \uff08b\uff0d3\uff092\u22650 \u56e0\u4e3a\u4e24\u4e2a\u4e0d\u5c0f\u4e8e0\u7684\u6570\u76f8\u52a0\u7b49\u4e8e0\u5219 \u5b83\u4eec\u4e00\u5b9a\u90fd\u4e3a0 \u6240\u4ee5 \u258fa\uff0b1/2\u258f\u22480 a=-1/2 \uff08b\uff0d3\uff092\u22480 b=3
7.\u597d\u50cf\u6709\u95ee\u9898
\u5bf9\u4e8e\u6c42\u4ee3\u6570\u5f0f\uff0c\u5305\u62ec\u5408\u5e76\u540c\u7c7b\u9879\uff0c\u63d0\u53d6\u516c\u56e0\u5f0f\uff0c\u5148\u7b97\u62ec\u53f7\u5185\u7684\uff0c\u518d\u7b97\u62ec\u53f7\u5916\u7684\u7b49\u8bb8\u591a\u65b9\u6cd5\u3002
\u4e0d\u8981\u5c06\u4f5c\u4e1a\u7ed9\u522b\u4eba\u505a\uff0c\u56e0\u4e3a\u8fd9\u6837\u4f60\u6839\u672c\u6ca1\u5b66\u5230\u4ec0\u4e48\uff0c\u505a\u4e0d\u6765\uff0c\u95ee\u95ee\u8001\u5e08\u540c\u5b66\u5427\uff0c\u8fd9\u6837\u4f60\u624d\u80fd\u5b66\u5230\u4e1c\u897f\uff0c\u624d\u80fd\u4e0d\u518d\u7528\u767d\u5ea6\u4e86\u3002
\u89e3\uff1a\u8bbe\u7532\u6709x\u679a\uff0c\u4e59\u6709y\u679a\uff0c\u4e19\u6709z\u679a\u90ae\u7968\u3002
\u7531\u9898\u610f\u53ef\u5f97\uff1ax-y=2 (1) z-x=4 (2) x+y-z=6 (3)
\u7531\uff081\uff09\u53ef\u5f97\uff1ax=2+y \uff084\uff09
\u628a\uff084\uff09\u4ee3\u5165\uff082\uff09\u5f97\uff1az-(2+y)=4 (5)
\u7531\uff085\uff09\u53ef\u5f97\uff1az=4+2+y (6)
\u628a\uff084\uff09\u3001\uff086\uff09\u4ee3\u5165\uff083\uff09\u5f97\uff1a
(2+y)+y-(4+2+y)=6
\u6240\u4ee5y=10
\u628ay=10\u4ee3\u5165(4)\u5f97\uff1ax=2+10=12
\u628ay=10\u4ee3\u5165(6)\u5f97\uff1az=4+2+10=16
\u65b9\u7a0b\u7ec4\u89e3\uff1ax=12 y=10 z=16
\u7b54\uff1a\u7532\u670912\u679a\u90ae\u7968\uff0c\u4e59\u670910\u679a\u90ae\u7968\uff0c\u4e19\u670916\u679a\u90ae\u7968\u3002
2.如图，已知∠1=100°，∠2=140°，求∠3的度数。（∠1和∠2是外角，∠3是内角）（
120）°
3.在直角三角形abd中，∠c为直角，∠b：∠c=1：4，求∠a的度数
.∠a的度数是(130）°
4.如图，在△abc中，∠c=90°，∠b=∠bac，d是bc上一点，且∠bad=20°，求∠adc的度数
（160）°
5.将衣服三角板叠放在一起，是直角定点重合于点o，则∠boc+∠aod=）度
(180）°
6.在△abc中，∠a=42°，顶点b的一个外角为135°，则顶点c的一个外角x的度数为（93
）°
根据三角形内角和180。则角adb就等于180-(45+35)=100度，又因为角cda与角adb互补所以角cda为180-100=80
先画个图.就可以得知角B为45度,角BAD为35度,根据三角形内角和180度定理,得出角BDA为180-45-35=100度
所以角ADC=180-100=80度
外角定理
80度
180-(180-35-45)=35+45=80
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