学年

質問の種類

数学 高校生

この問題はなぜD1が完全平方式となればいいと言えるんですか?

重要 例題 51 2次式の因数分解 (2) (0①①①①① 4x2+7xy-2y²-5x+8y+kx,yの1次式の積に因数分解できるように, 定数kの値を定めよ。 また, そのときの因数分解の結果を求めよ。 [類 創価大〕 |基本 20,46 CHART OLUTION 2次式の因数分解 =0 とおいた2次方程式の解を利用 (与式)=0 とおいた方程式をxの2次方程式とみたとき (yを定数とみる), 判別 —(7y—5)—√D₁ 式をD, とすると、与式は4{x-(7y-5)+√D}{x-(y-5)-D} の形 8 8 に因数分解される。D1はyの2次式であり,このときの因数がx,yの1次式と なるための条件は √DIがyの1次式⇔ D1 が完全平方式 すなわち D=0 として,この2次方程式の判別式D2 が 0 となればよい。 解答 (与式)=0 とおいた方程式をxの2次方程式とみて、 4x²+(7y-5)x-(2y²-8y-k)=0 ① の判別式をDとすると まれている。これまでと同 っと D=(7y-5)2+4・4(2y²-8y-k)=81y²-198y+25-16k 与式がxとyの1次式の積に分解されるための条件は、 ①の解 がyの1次式となること,すなわち D1 がyの完全平方式とな ることである。 の D=0 とおいたの2次方程式 81y²-198y+25-16k=0 0 判別式をD2 とすると (2+8)(€ 9) = (86) D₂=(-99)²-81(25-16k)=81{11²—(25—16k)}=81(96+16k) 4 D2=0 となればよいから 96+16k = 0 よって x= ゆえに ...... このとき, D1=81y²-198y+121=(9y-11)2 であるから, ① の解は すなわち x=- , -2y+2 y-3 4 $=44-830-81 m2;&ck: __(7y-5)±√(9y-11) __(7y-5)±(9y-11) 8 8 MURDER inf. 恒等式の考えにより 解く方法もある。(解答編 および p.55 EXERCISES 15 参照 ) (5x)=4(x−y=³){x−(−2y+2)} kid =(4x-y+3)(x+2y-2) ◆ D1 が完全平方式 ⇔ 2次方程式 D1=0 が重 解をもつ =) AGOR adot 計算を工夫すると 992(9.11) 2=81112 は、 ←√(9y-11)^=|9y-11| であるが, ±がついて いるから, 9y-11の絶 対値ははずしてよい。 (括弧の前の4を忘れな - PRACTICE・・・・ 51④ を定数とする2次式 x2+3xy+2y2-3x-5y+k がx,yの1次式の積に因数分解 できるときの値を求めよ。 また, そのときの因数分解の結果を求めよ。 [東京大 2章 7 解と係数の関係

未解決 回答数: 1
英語 中学生

文章の内容があまり理解できません。 ざっくりで良いので内容を解説して欲しいです🙇🏻‍♀️

About 50 years ago, I lived in Los Angeles, California. My father took care of my younger sister and me. We played baseball every weekend. My sister and I loved baseball. I knew that my father had a "hero. His name was Ken Smith. He played for a team in *St. Louis. Its name was the Red Birds. My father said that Ken was the greatest player of all *major league baseball players at that time. I also became a big fan of Ken Smith, so I wanted to be like Ken Smith very much. That summer was special because my father *took my sister and me to St. Louis. We went there and came home by *plane. We were going to meet Ken Smith. I almost couldn't believe that. My father's best friend had a big *company in St. Louis, and he knew some of the very important people of the Red Birds. He also knew Ken Smith well. We stayed at my grandmother's house in St. Louis, She said to me, "Jack, I have something special for you." That was a ball with an *autograph by Smith. An *injured player of the Red Birds was in the hospital, and my grandmother worked there. She told him my story, and he got Smith's autograph on the ball. She knew that A but she gave the ball to me. I was sorry for my father, but I was very happy. I liked Ken Smith more. The next day was an exciting day for us. My father's friend helped us, and we could meet Ken Smith before the game. I thought Smith would be kind and big, and I was right. Then I showed him the ball from my grandmother. We talked about it. He asked me about the way to practice baseball, and I talked to him *proudly. *In front of Ken, I felt that I needed to do so. I wanted to be a great baseball player. He *understood. That night we watched a night game of the Red Birds. During the game, I *held my ball, and looked at it many times. A man talked to me. "New ball?" he asked. "Yes, with an autograph," I said and smiled. "Who?" he asked. "Ken Smith," I said proudly. "Really? I don't believe you." "Here, look." "Wow! I'll get it for 20 *dollars right now!" "No, give my ball back to me, please," I said. "You've got a very special thing. Take good care of it!" he said. I knew that the ball was a *treasure for me. The next day, 3I felt it took a long time to get back to Los Angeles. I was excited and I told my friends about my experience with Ken Smith in St. Louis. No one believed me, but I thought that I would never forget my happy feelings then. About 20 years later, my father died. Before the *funeral, I *remembered that he once *asked us to put his *baseball cards and a *baseball in his *casket. I wanted to use my baseball with Ken's autograph for him. My sister also liked my idea. The ball was with my father. A few years later, my sister *got married. Before *wedding finished, my sister started a story. She was a *flight attendant and *flew with the baseball players of Los Angeles Blue Sky and the manager Tom Baylor. Then she told him the story of my old baseball. He understood her story very well. Baylor was a friend of Ken Smith and *promised her to get another ball with Ken's autograph for me. Ken *was very impressed by her story, and sent a baseball with his autograph to Baylor. The ball was then sent to my sister. When she finished the story, I looked up and saw that she was holding a ball. "I have B threw it to me. I remembered that summer and my grandmother. I felt like a child again when I was going home. she said and

回答募集中 回答数: 0
英語 高校生

my way2lesson9のQ&Aの1.2.3の答えが分かりません。どなたか教えて頂きたいです

15 Section 1 ●チャップリンは、どのような幼少時代を送ったのでしょうか。 ・チャールズ・チャップリンは有名な俳優で、プロデューサーでした。 彼は人類 MEL created many films about humanity, peace, and equality. 彼は喜屋 He was called the King of Comedy". Before he becamg/ なる前 famous, However, his Slife was quite tragic. 1887年10 チャップリ 5 Chaplin was 2人とも保存でis father both actors. でつまれました。彼の 親は .horn in London in 1889. His parents were Foreft Q&A ものでした。 家族をはなれました。彼の母、そして彼自身にとっ the family when Charlie was only one year old. For his mother, brother, and himself, 人生は簡単ではありませんでした。 彼女は精神病にくるしみ始めました。 to suffer from illness. けっきょくまャーリーはまずしい子ども Eventually, Charlie was Sent to a 達のための 送られました。 ◎こどくや house for poor children. Feeling lonely and miserable, he spent most of his childhood there. 金を稼ぐ She began When Chaplin 彼の母が病気になり チャップリンが5歳の時。 was five years old, his mother fell ill I and lost her job. Send to work very hard to 働きましたが 十分なmake enough money. living, but she could not Charles Chaplin 幼少時代のチャップリン (中央) 1. Did Chaplin create films only about equality? 2. How was his family's life? 3. Who began to suffer from mental illness? producer [pradjan film(s) (p.123) Charles Chaplin チャールズ・チャップリン (1889~1977) 6 Charlie チャーリー 《Charles の愛称》 10-11 make a living 生計を立てる 9 fall ill 病気になる 11 make money 金を稼ぐ bumanity [hju:man るため to makeはじめに a ・できませんでした。 king ki comedy [kúmədi] ◆Charlie (tfa:rli] mental [ eventual [ivèntjuali] lonely misera [mizrabl 3 the King of Cor

未解決 回答数: 1