初二数学,帮忙解答下,只要22至25题的答案,谢谢!
来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/07/13 09:55:55
初二数学,帮忙解答下,只要22至25题的答案,谢谢!
http://wenku.baidu.com/view/ffcbbe838762caaedd33d44c.html
http://wenku.baidu.com/view/ffcbbe838762caaedd33d44c.html
![初二数学,帮忙解答下,只要22至25题的答案,谢谢!](/uploads/image/z/3879079-7-9.jpg?t=%E5%88%9D%E4%BA%8C%E6%95%B0%E5%AD%A6%2C%E5%B8%AE%E5%BF%99%E8%A7%A3%E7%AD%94%E4%B8%8B%2C%E5%8F%AA%E8%A6%8122%E8%87%B325%E9%A2%98%E7%9A%84%E7%AD%94%E6%A1%88%2C%E8%B0%A2%E8%B0%A2%21)
22、
![](http://img.wesiedu.com/upload/e/13/e13ecd6377eca009258a490e7e62b5cf.jpg)
23、(1)把E(-8,0)代入直线y=kx+6中得:0=-8k+6,解得:K=3/4
所以直线是:Y=3/4X+6 即P坐标是:(x,3/4x+6)
所以:OPA的面积是:S=1/2*|OA|*|Yp|=1/2*6*(3/4x+6)=9/4x+18
x的取值范围是:-8<x<0
(2)s=27/8代入上式中得:
27/8=9/4x+18
x=-6.5 y=3/4*(-6.5)+6=9/8
即当P点运动到(-6.5,9/8)时面积是27/8
24、
![](http://img.wesiedu.com/upload/d/a8/da8385f87644c8ea35597b805713fbca.jpg)
![](http://img.wesiedu.com/upload/2/f7/2f7569ede1ce3355b1d605e5fc3f6519.jpg)
![](http://img.wesiedu.com/upload/3/6a/36a3773969b2c297d6d0e14980793ba3.jpg)
![](http://img.wesiedu.com/upload/c/ff/cff40ad41d37beefc021c8e85918ee08.jpg)
![](http://img.wesiedu.com/upload/e/13/e13ecd6377eca009258a490e7e62b5cf.jpg)
23、(1)把E(-8,0)代入直线y=kx+6中得:0=-8k+6,解得:K=3/4
所以直线是:Y=3/4X+6 即P坐标是:(x,3/4x+6)
所以:OPA的面积是:S=1/2*|OA|*|Yp|=1/2*6*(3/4x+6)=9/4x+18
x的取值范围是:-8<x<0
(2)s=27/8代入上式中得:
27/8=9/4x+18
x=-6.5 y=3/4*(-6.5)+6=9/8
即当P点运动到(-6.5,9/8)时面积是27/8
24、
![](http://img.wesiedu.com/upload/d/a8/da8385f87644c8ea35597b805713fbca.jpg)
![](http://img.wesiedu.com/upload/2/f7/2f7569ede1ce3355b1d605e5fc3f6519.jpg)
![](http://img.wesiedu.com/upload/3/6a/36a3773969b2c297d6d0e14980793ba3.jpg)
![](http://img.wesiedu.com/upload/c/ff/cff40ad41d37beefc021c8e85918ee08.jpg)