1/5单选题
难度：
1.现有一块长80cm、宽60cm的矩形钢片，将它的四个角各剪去一个边长为xcm的小正方形，做成一个底面积为ycm2的无盖的长方体盒子，则y与x之间的函数关系式为（ ）
| A | y=x2-70x+1200 |
| B | y=x2-140x+4800 |
| C | y=4x2-280x+4800 |
| D | y=4800-4x2 |
- 提示1：
- 5Yip55So546w5pyJ5LiA5Z2X6ZW/ODBjbeOAgeWuvTYwY23nmoTnn6nlvaLpkqLniYfvvIzlsIblroPnmoTlm5vkuKrop5LlkITliarljrvkuIDkuKrovrnplb/kuLp4Y23nmoTlsI/mraPmlrnlvaLvvIzov5vogIzooajnpLrlh7rml6Dnm5bnmoTplb/mlrnkvZPnm5LlrZDlupXovrnnmoTplb/vvIzov5vogIzlvpflh7p55LiOeOS5i+mXtOeahOWHveaVsOWFs+ezu+W8j++8jg==
正确答案：Qw==
6Kej77ya55Sx6aKY5oSP5Y+v5b6X77yaeT3vvIg4MC0yeO+8ie+8iDYwLTJ477yJPTR4PHN1cD4yPC9zdXA+LTI4MHgrNDgwMO+8jjxicj7mlYXpgInvvJpD77yO
2/5单选题
难度：
2.三角形的一边长与这边上的高都为xcm，其面积是ycm2，则y与x的函数关系为（ ）
| A | y=x2 |
| B | y=2x2 |
| C | y= x2 |
| D | y= x2 |
- 提示1：
- 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
正确答案：Qw==
6Kej77ya55Sx5LiJ6KeS5b2i55qE6Z2i56ev5YWs5byPPTxpbWcgd2lkdGg9NiBoZWlnaHQ9NDIgc3JjPSJodHRwczovL3AxLnFpbmdndW8uY29tL0cxL00wMC9CNy9BNS9yQkFDRTFWMDl5bWlWMjBzQUFBQkhHak1qRjA2NDcucG5nIj7Dl+W6lcOX6auY5b6X77yaPGJyPnk9PGltZyB3aWR0aD02IGhlaWdodD00MiBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwL0I3L0E1L3JCQUNFMVYwOXltaVYyMHNBQUFCSEdqTWpGMDY0Ny5wbmciPng8c3VwPjI8L3N1cD7vvI48YnI+5pWF6YCJQ++8jg==
3/5单选题
难度：
3.把一根长为50cm的铁丝弯成一个长方形，设这个长方形的一边长为x（cm），它的面积为y（cm2），则y与x之间的函数关系式为（ ）
| A | y=-x2+50x |
| B | y=x2-50x |
| C | y=-x2+25x |
| D | y=-2x2+25 |
- 提示1：
- 55Sx6ZW/5pa55b2i55qE6Z2i56evPemVv8OX5a695Y+v5rGC6Kej77yO
正确答案：Qw==
6Kej77ya6K6+6L+Z5Liq6ZW/5pa55b2i55qE5LiA6L656ZW/5Li6eGNt77yM5YiZ5Y+m5LiA6L656ZW/5Li677yIMjUteO+8iWNt77yMPGJyPuS7pemdouenr3k9eO+8iDI1LXjvvIk9LXg8c3VwPjI8L3N1cD4rMjV477yOPGJyPuaVhemAiUPvvI4=
4/5单选题
难度：
4.在半径为4cm的圆中，挖去一个半径为xcm的圆面，剩下一个圆环的面积为ycm2，则y与x的函数关系式为（ ）
| A | y=πx2-4 |
| B | y=π（2-x）2 |
| C | y=-（x2+4） |
| D | y=-πx2+16π |
- 提示1：
- 5Ymp5LiL6Z2i56evPeWNiuW+hOS4ujTnmoTlnIbnmoTpnaLnp68t5Y2K5b6E5Li6eOeahOWchueahOmdouenrz0xNs+ALc+AeDxzdXA+Mjwvc3VwPj0tz4B4PHN1cD4yPC9zdXA+KzE2z4A=
正确答案：RA==
6Kej77ya5Y2K5b6E5Li6NOeahOWchueahOmdouenrzE2z4DvvIw8YnI+5Y2K5b6E5Li6eOeahOWchueahOmdouenr8+AeDxzdXA+Mjwvc3VwPu+8jjxicj7lm6DogIzlh73mlbDop6PmnpDlvI/mmK/vvJp5PS3PgHg8c3VwPjI8L3N1cD4rMTbPgO+8jjxicj7mlYXpgIlE77yO
5/5单选题
难度：
5.如图，四边形ABCD中，∠BAD=∠ACB=90°，AB=AD，AC=4BC，设CD的长为x，四边形ABCD的面积为y，则y与x之间的函数关系式是（ ）
| A |  |
| B |  |
| C |  |
| D |  |
- 提示1：
- 5Zub6L655b2iQUJDROWbvuW9ouS4jeinhOWIme+8jOagueaNruW3suefpeadoeS7tu+8jOWwhuKWs0FCQ+e7lUHngrnpgIbml7bpkojml4vovaw5MMKw5Yiw4pazQURF55qE5L2N572u77yM5rGC5Zub6L655b2iQUJDROeahOmdouenr+mXrumimOi9rOWMluS4uuaxguair+W9okFDREXnmoTpnaLnp6/pl67popjvvJs=
- 提示2：
- 5qC55o2u5YWo562J5LiJ6KeS5b2i57q/5q615LmL6Ze055qE5YWz57O777yM57uT5ZCI5Yu+6IKh5a6a55CG77yM5oqK5qKv5b2i5LiK5bqVREXvvIzkuIvlupVBQ++8jOmrmERG5YiG5Yir55So5ZCreOeahOW8j+WtkOihqOekuu+8jOWPr+ihqOekuuWbm+i+ueW9okFCQ0TnmoTpnaLnp6/vvI4=
正确答案：Qw==
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