分解因式整式化简练习题及答案.doc

25.如果单项式与是关于x、y的单项式,且它们是同类项.（1）求的值.（2）若=0,且xy0,求的值.26.先化简再求值。（1）,其中x=.（2）已知,计算3A-2B.（3）已知,求的值.（4）若,求的值.27.某同学做一道数学题,误将求“A-B”看成求“A+B”, 结果求出的答案是.已知,请正确求出A-B.28.有理数a、b、c在数轴上对应点为A、B、C,其位置如图所示, 试去掉绝对值符号并合并同类项:.29.某移动通讯公司开设了两种通讯业务:“全球通”使用者缴50元月租费, 然后每通话1分钟再付话费0.4元;“快捷通”不缴月租费,每通话1分钟,付话费0,6 元（本题的通话均指市内通话）.若一个月内通话x分钟,两种方式的费用分别为y1 元和y2元.（1）用含x的代数式分别表示y1和y2,则y1= ,y2= .（2）某人估计一个月内通话300分钟,应选择哪种移动通讯合算些?30.探索规律。（1）计算并观察下列每组算式: （2）已知2525=625,那么2426=_.（3）从以上的过程中,你发现了什么规律,你能用语言叙述这个规律吗?你能用代数式表示设这个规律吗?31.在一次水灾中，大约有个人无家可归，假如一顶帐篷占地100米，可以放置40个床位，为了安置所有无家可归的人，需要多少顶帐篷？这些帐篷大约要占多少地方？估计你的学校的操场可安置多少人？要安置这些人，大约需要多少个这样的操场？32.化简：（x2-9）.33.已知P=，Q=（x+y）2-2y（x+y），小敏、小聪两人在x=2-y=-1的条件下分别计算了P和Q的值小敏说P的值比Q大，小聪说Q的值比P大请你判断谁的结论正确，并说明理由56.57.58.59.60.，其中。61.已知当时，求 的值。62.63.64.65.66.分解因式：（1）;（2）已知求的值67.化简：.68.化简求值：，其中a=69.先化简再求值：，其中a满足a2-a=070.先化简（1+，然后请你给a选取一个合适的值，代入求值25.考点:15.1 整式的加减试题解析:（1）先求a=3,（7a-22）2002=1（2）a=3时,2mx3y-5nx3y=0,又xy 0 得2m-5n=0则原式=0答案:见解析 26.考点:15.1 整式的加减试题解析:（1）原式=-x-3y值为1（2）4x2+18x-31（3）原式=2（m2+3mn）+5,值为15（4）原式=答案:见解析 27.考点:15.1 整式的加减试题解析:答案:A-B=2A-（A+B）=5x2-4x-17 28.考点:15.1 整式的加减试题解析:答案:原式=-c-（-b-c）+（a-c）+（-b-a）=-c 29.考点:15.1 整式的加减试题解析:（1）y1=50+0.4x y2=0.6x（2）x=300时,y1=170 y2=180 故选“全球通”合算答案:见解析 30.考点:15.1 整式的加减试题解析:1.略 2.624 3.（n-1）（n+1）=n2-1答案:见解析 31.考点:15.4 整式的除法试题解析:答案:6250顶帐篷，占米的地方，后面答案视操场的大小定。 32.考点:15.5 因式分解试题解析:答案:x+3 33.考点:15.5 因式分解试题解析:P=x+y，当x=2，y=-1时，P=1，当Q=（x+y）2-2y（x+y）=x2-y2，当x=2，y=-1时，Q=3，PQ，小聪的结论正确答案:见解析56.考点:15.4 整式的除法试题解析:答案: 57.考点:15.4 整式的除法试题解析:答案: 58.考点:15.4 整式的除法试题解析:答案: 59.考点:15.4 整式的除法试题解析:答案: 60.考点:15.4 整式的除法试题解析:答案: 61.考点:15.4 整式的除法试题解析:答案: 62.考点:15.4 整式的除法试题解析:答案: 63.考点:15.4 整式的除法试题解析:答案: 64.考点:15.4 整式的除法试题解析:答案: 65.考点:15.4 整式的除法试题解析:答案: 66.考点:15.5 因式分解试题解析:答案:（1）a（a-b）2 （2）（a-b）2+（b-c）2+（a-c）2=6 67.考点:15.5 因式分解试题解析:答案: 68.考点:15.5 因式分解试题解析:答案: 69.考点:15.5 因式分解试题解析:答案:a2-a-2=-2 70.考点:15.5 因式分解试题解析:答案:化简结果a+2，a不能取值2 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline . Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope