一道六年纪的数学题爸爸某年存入银行一笔钱,定期一年,当时的一年期年利率2.79%/到期后,爸爸连本带利拿到10223.2

一道六年纪的应用题
甲,乙两人沿着直径为200米的圆形跑道同时背向而行,出发4分后两人第一次相遇,这时甲走了全程的五分之三,乙每分走多少米?

化简m√-1/m
答案上说的是把m放进根号内,得√-m²·(1/m).
为什么把m放进根号内就成负值了?
还有一道
六次根号下4a²-4a+1=三次根号下1-2a，求实数a的取值范围。
那么 六次根号下4a²-4a+1就等于次根号下(2a-1)²= 三次根号下2a-1 a＞1/2
② 0 a=1/2
三次根号下1-2a a＜1/2
所以a≤1/2 ①
①到②是怎么来的？

问你们一道六年纪数学题
一项工程,甲独做要50天完成,乙独做要75天完成,合作中途,乙因有事耽误了几天年,回来以后继续和甲合作,甲乙两人花了40天才完成这项工程,请问乙休息了几天?
麻烦给我具体的算式

一道六年纪的数学体
观察下面的等试：
3＊1．5＝3＋1．5
6＊1．2＝6＋1．2
9＊1．125＝9＋1．125
你发现了什么道理?

一道六年纪的英语题（完形填空）高手请进
There are many kangaroos(袋鼠) in Australia.you can __16__them not only in__17__,but also everywhere.kangaroos are very popular in Australia.kangaroos have very__18__legs(腿),so they are very good at(擅长与)__19__.Their tails are strong,too.---so when they want to have a__20__,they rest on their __21__.
kangaroos are __22__very good at looking__23__their .__24__
kangaroos keep their babies safe in their__25__
( )16.A read B see C watch D look
( )17.A homes B rooms C zoos D gardens
( )18.A fast B large C small D strong
( )19.A jumping B walking C running D flying
( )20.A look B rest C talk D swim
( )21.A tails B legs C feet D arms
( )22.A ever B just C alse D once
( )23.A like B after C out D over
( )24.A Father B Sister C Brother D Mother
( )25.A hearts B heads C pockets D hands
英语