用加减消元法求解下列方程组_刷题宝

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用加减消元法求解下列方程组

上一题下一题 0.0难度选择题更新时间:2012-07-06 08:36:38

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同类题1

PM2.5是指大气中直径小于或等于2.5微米的颗粒物，空气中转化成PM2.5的气体污染物主要有二氧化硫、氮氧化物、氨气、挥发性有机物．其中的SO₂对植物的危害表现在能直接破坏植物的叶肉组织，使叶片失绿，严重危害植物的生长发育，浓度高时，会使植物枯死．下面是某研究小组为探究不同浓度SO₂对不同植物生长影响的相关实验．

材料用具：无水亚硫化钠和稀硫酸（1：4），新鲜菠菜、油菜、青菜，330mL矿泉水瓶若干个，计时器，温度计，透明胶布等．

同类题2

广西发展自古以来与国家统一民族融合密切相关，广西历史上最早设郡管理是在（）

同类题3

Hans Bethe
The late German-American physicist Hans Bethe once described himself as “the H-bomb’s midwife（接生婆）”. He left Nazi Germany in 1933, after which he helped develop the first atomic bomb（原子弹）, won the Nobel Prize in Physics in 1967 for his contribution to the theory of nuclear reactions（核反应）and advised controls over nuclear weapons（武器）for the peaceful use of the nuclear energy

Francis Crick
The late Francis Crick, one of Britain’s most famous scientists, won the Nobel Prize in Physiology（生理学）or Medicine in 1962. He is best known for his discovery with James Watson and Maurice Wilkins, the double helix structure（双螺旋结构）of the DNA, though he also made important contributions in other fields. He died in 2004.

Peter Hall
Sir Peter Hall’s life in the theatre has seen him running the Arts Theatre, founding the Royal Shakespeare Company when he was only 29, and directing the National Theatre. He also directed Akenfielf for London Weekend Television and runs the Peter Hall Company, which has 40 productions worldwide to its name.

同类题4

如图，一固定的竖直汽缸由一大一小两个同轴圆筒组成，两圆筒中各有一个活塞，已知大活塞的质量为m₁=2.50kg，横截面积为s₁=80.0cm²，小活塞的质量为m₂=1.50kg，横截面积为s₂=40.0cm²，两活塞用刚性轻杆连接，间距保持为l=40.0cm，汽缸外大气的压强为p=1.00×10⁵Pa，温度为T=303K，初始时大活塞与大圆筒底部相距 $\frac{1}{2}$ ，两活塞间封闭气体的温度为T₁=495K，现汽缸内气体温度缓慢下降，活塞缓慢下移，忽略两活塞与汽缸壁之间的摩擦，重力加速度大小g取10m/s²，求：

同类题5

如图，ABD为竖直平面内的轨道，其中AB段是水平粗糙的、BD段为半径R=0.4m的半圆光滑轨道，两段轨道相切于B点．小球甲从C点以速度υ₀沿水平轨道向右运动，与静止在B点的小球乙发生弹性碰撞．已知甲、乙两球的质量均为m，小球甲与AB段的动摩擦因数为μ=0.5，C、B距离L=1.6m，g取10m/s²．（水平轨道足够长，甲、乙两球可视为质点）

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