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数学 高校生

chartsolutionがどういうことかわかりません。

重要例題/9 方程式の共通解 のOOOO 2つの2次方程式 2.x°+kx+4=0, x*+x+k=0 がただ1つの共通の実数 解をもつように, 定数んの値を定め, その共通解を求めよ。 基本75 CHART OSOLUTION 方程式の解 x=α が解 =e を代入して方程式が成り立つ 2つの方程式の共通解を x3o とすると, それぞれの式に x=αを代入した 2°+ ka+4=0, α"+α+k=0 が成り立つ。 これを α, kについての連立方程式 とみて解く。実数解という条件に注意。 解答 共通解をx=α とすると 2g°+ka+4=0 … 0, x=α を代入した①と 2の連立方程式を解く。 a+α+k=0 O-2×2 から (k-2)α+4-2k=0 (k-2)a-2(k-2)=0 (R-2)(α-2)=0 合の項を消す。 すなわち よって ゆえに k=2 または α=2 合共通の実数解が存在する ための必要条件であるか [1] k=2 のとき 2つの方程式は, ともに x°+x+2=0 となる。 その判別式をDとすると ら,逆を調べ十分条件で あることを確かめる。 D=1?-4·1·2=-7 * ax°+ bx+c=0 の判別 式は D=6°-4ac D<0 であり,実数解をもたないから, k=2 は適さない。 [2] α=2 のとき 2から 22+2+k=0 ゆえに k=-6 このとき2つの方程式は *2(x-1)(x-2)=0, (x-2)(x+3)=0 2x?-6x+4=0 0', x°+x-6=0 2の解は x=2, -3 となり,O' の解は x=1, 2 よって, 確かにただ1つの共通解 x=2 をもつ。 [1], [2] から k=-6, 共通解は x=2

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英語 中学生

英検2級の過去問です。 この文章を約4分の1くらいに「要約」したいのですが、自分では上手く書けませんでした💦 誰か書いてくれませんか?参考にしたいです。

Grade 2 3 C Building a Better Future Estonia is a country in northern Europe. Before World War II, it was an independent country, but by the end of the war, it was part of the Soviet Union. In those days, there was a shortage of houses in many parts of the Soviet Union, so the government built many apartment buildings. These were meant to be temporary homes, and they were not designed or built well. After the Soviet Union broke up in 1991, Estonia and other countries became independent again. Most of these countries have been destroying their old apartment buildings. Estonia, however, is turning its apartment buildings into environmentally friendly homes that use energy efficiently. The project began in 2016 with 17 apartment buildings in Tartu, a city in the south of the country, and is known as SmartEnCity. Estonia is now a member of the European Union (EU), and it received financial help from the EU for the project. The aim is not only to reduce the amount of energy consumed by the apartments, but also to turn them into modern, good-looking homes. Work on the 17 apartment buildings in Tartu has now been completed. Changes have been made to prevent heat from escaping through the walls and windows. A new, efficient heating system has been added. Each apartment has a control panel which lets residents monitor and control the amount of energy they consume. As a result, the residents now use 80 percent less gas to heat their apartments. Also, solar panels have been installed on the buildings, and these produce three times more electricity than the residents need. Some critics said the project would be a waste of money. However, so far, it seems to be working. The EU paid for half of the cost, and the rest was paid for by residents using money borrowed from banks. The residents are spending 1less than_they used to on energy bills,/ so they have extra money to repay the loans. Moreover, the work on the apartments has improved the way the city looks. The Estonian government hopes to upgrade some of the other 6,000 old apartment buildings in the country in a similar way. CDE 22 公益財団法人日本英語検定協会 無断転載複製を禁じます 2021年度第1回検定一次試験(2級) I2 無断転載複製を禁じます

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