七年级数学讲义

1、专业好文档1、 下列运算：；，其中不正确的有 。2、 已知：的值为 。3、 已知的值为 。4、 = 。5、 若= 。6、 = 。7、 一个棱长为的正方体，在某种物质的作用下，棱长以每天扩大到原来的倍的速度膨胀，则10天后该正方体的体积为 。8、 的个位数字是 。幂的大小比较方法：（1）直接计算法 已知a，b,c分别为，则a,b,c按从小到大的顺序排列的结果是 。（2） 差值比较法 利用比较的大小。（3） 商值比较法 已知，那么p，q的大小关系是？（4） 底数比较法 数的大小关系是？（5） 指数比较法 若，则a，b，c的大小关系是？（6） 乘方比较法 已知：，比较a和b的大小。（7） 倒数比较法

2、 比较的大小。(8) 中间数比较法 比较的大小。1、 若= 。2、 已知= 。3、 计算：（n为正整数）4、 解关于x的方程：1、 计算的结果为 。2、 化简的结果是 。3、 若，则适合条件的m，k的值分别等于？4、 若的值是？5、 先化简，后求值。 ，其中x=1,y=2.6、 我们规定下列运算： 7、 先化简，再求值：（1） 其中x=5 y=1（2） 其中 （3） 其中 x=28.已知 求 的值。9.已知 求 的值。10.解方程：11.若多项式与的积不含x三次方的项，求a和b的值。12.如图，正方形卡片a类，b类和长方形卡片c类若干张，如果要拼一个长为（a+2b），宽为（a+b）的大长方形，

3、则需要c类卡片 张。（1） 根据前面各式的规律可得： （n为正整数）（2） 利用上述规律求的值。winger tuivasa-sheck, who scored two tries in the kiwis 20-18 semi-final win over england, has been passed fit after a lower-leg injury, while slater has been named at full-back but is still recovering from a knee injury aggravated against usa.both sid

4、es boast 100% records heading into the encounter but australia have not conceded a try since josh charnleys effort in their first pool match against england on the opening day.aussie winger jarryd hayne is the competitions top try scorer with nine, closely followed by tuivasa-sheck with eight.but it

5、 is recently named rugby league international federation player of the year sonny bill williams who has attracted the most interest in the tournament so far.the kiwi - with a tournament high 17 offloads - has the chance of becoming the first player to win the world cup in both rugby league and rugby

6、 union after triumphing with the all blacks in 2011.id give every award back in a heartbeat just to get across the line this weekend, said williams.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th a

7、nniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened

8、 disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. i

9、n a statement the russian side added: we found no racist insults from fans of cska. baumgartner the disappointing news: mission aborted.the supersonic descent could happen as early as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to be very calm -

10、 winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilomete

11、rs), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i w

12、ould assume, he will slowly step out onto something resembling an olympic diving platform.they blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the kiwis in manchester.five years ago they cruised through to the final and so far history has repeat

13、ed itself here - the last try they conceded was scored by englands josh charnley in the opening game of the tournament.that could be classed as a weakness, a team under-cooked - but i have been impressed by the kangaroos focus in their games since then.they have been concentrating on the sort of stu

14、ff that wins you tough, even contests - strong defence, especially on their own goal-line, completing sets and a good kick-chase. theyve been great at all the unglamorous stuff that often goes unnoticed in the stands but not by your team-mates.it is as though their entire tournament has been preparation for the final.in johnathan thurston, cooper cronk, cameron smith and either billy slater or greg inglis at full-back they have a spine that is unmatched in rugby league. they have played in so many high-pressure games - a priceless asset going into saturday.the kiwis are a lot less experienc