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数学 高校生

基本問題の例題(2)がしょうなりいじょう7になってるけど practice33の(2)は<21になってるんですけどどういう意味で違うんですか?教えて欲しいです。

PR ③33 (1) 不等式x+1/18/1/2x-12/2 を満たす正の奇数xをすべて求めよ。 6 3 (2) 不等式 5(x-a)-2(x-3) を満たす最大の整数が2であるとき,定数aの値の範囲を求 めよ。 (11/03/12/12/28 x一 6 x+ 整理して -4x>-28 よって x <7 これを満たす正の奇数xは 1,35 6x+1>10x-27 (2) 5(x-a)s-2(x-3) 5 xs- ① を満たす最大の整数が2となるのは 5a+6 25 43 74 のときである。 ゆえに 14≦5a+6<21 よって CHART & THINKING 1次不等式の整数解 数直線を利用 まずは、与えられた不等式を解く。 (1) 2桁の自然数x≧10 5a +6 7 解答 (1) 6x+8(6-x) > 7 から 41 x < -=20.5 ゆえに Sa+6 3 7 ①を満たす最大の整数 xは2桁の自然数であるから 10≤x≤20 求める自然数の個数は 567X のときである。 ゆえに 1 <2a≦2 よって 12/2<as1 +86-x) を満たす2桁の自然数xの個数を求めよ。 基本 29.32 (2) 不等式 5(x-1)<2(2x+α) を満たすxのうちで, 最大の整数が6であ るとき,定数aの値の範囲を求めよ。 x の整数が6となるのはAがどのような値の範囲にあるかを 考えよう。 は x<A を満たすが,x=7 は x=6 x<A を満たさないことが条件となる。 -2x>-41 両辺に6を掛けて分母 を払う。 10 11 範囲を 10≦x≦n の形に表す。 この不等式を満たす整数の個数は? 2桁 7は含まれない。 SC ◆展開して整理。 (2) 不等式の解は x<A の形となる。 数直線上でAの値を変化させ, x <A を 20-10+1=11(個) (2) 5(x-1)<2(2x+α) から x2a +5 / ••・・・ ① ①を満たすxのうちで最大の整数が6となるのは 114 6<2a+57 2< これと不等式の解を合わせて、条件を満たす整数xの他の 20 41 2 5a +6 7 25+6 3 などとし 7 ないように等号の有無に 注意する。 -<3 とか 21 x 2a+5 7 ①を満たす最大の整数 x を満たす最大 A ◆展開して整理。 不等号の向きが変わる。 ◆解の吟味。 ◆展開して整理。 6<2a+5<7 とか 6≦2a+57 などとし ないように。 等号の有 無に注意する。 a=1 のとき, 不等式

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数学 高校生

例題47(2)の青い部分で何を言ってるのかよく分かりません。 青い部分以降もなぜそれをすれば答えが出るのかも教えて欲しいです。

2 第2章 高次方程式 Think x ²2 2次式の因数分解 (1) 複素数の範囲で考えて、次の式を因数分解せよ。依 ア 3xxのを求めよ。 例題 47 x-160 (2) xxy-6²-9x+ky+20 が1次式の積となるように熱の値 LONE を定めよ. |解答 考え方 (1) (与式)=0とおき、xの2次方程式を考えると,複素数の範囲で必ず解をもっ (2) まずxの2次式とみて因数分解し, これがx,yの1次式の積になると考える。 (1+AS)E 別解では, 「与えられた式が1次式の積で表される」 ⇒ (1) (ア) 31=0の解は, (2) SA )の形に因数分解できる」ことから( __(-1)±√(-1)-4・3・(-1)_1±√13 2.30 (沖縄)(増量)] x2+(y-9)x-6y2+ky+20=0 の判別式をDとすると,①の解は, x= 2 したがって, 与式は, x=- よって15 3x-x-1=3x-- (イ)x16=(x-4)(x+4)=(x-2)(x+2)(x+4人 3x²-x-1=0の2 x2+4=0の解は,x2=-4 より 解をα, βとすると、 したがって,x+4=(x-21)(x+2i) 左辺は よって, x-16=(x-2)(x+2)(x-2)(x+2i) の2次方程式 3x²-x-1 S __(y-9)±√D_9-y±√D と因数分解できる. 4 1+√13 6 √13)(x-1-√13) 6 (5)=(x-9-y+√D 2 3569 10 2 x=±2i x-9-y-√D (1) D=(y-9)²-4・1・(-6y2+ky+20 ) =y°-18y+81+24y²-4ky-80) == (S-88 =4(k+9k+14)=4(k+7)(k+2) したがって, 4(k+7)(k+2) = 0 よって, k=-7, -2 **** =25y^-2(9+2k)y+1=0 2(1)( したがって、与式がx,yの1次式の積になるのは, 根号の中のDがyの完全平方式であるときである. yについての2次方程式 25y²-2(9+2k)y+1=0 の 判別式をDとすると,D=0である. wimm D={(9+2k)}^-25・1=4k²+36k+56 )() の形で表す。 解の公式を用いる。 の係数3を忘れ ないこと ESTE =3(x-a)(x-β) と因数分解すること ができる. yの2次式 |完全平方式とは, ay-α)” の形のこと 完全平方式であるか ら、重解をもつ (判別式) = 0 100900-8+ x(+9)+* 注)Dがyについての2次式なので、Dをa(y-α)² と表すことができればDyの 1次式として表すことができるので、Dがyの完全平方 k-7 のとき D = ( 5y+1)^ k=2のとき D=(5y-1)²

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英語 高校生

この問題の答えを教えてください🙇 Elixir3三訂版です。

26 29 27 28 UNIT 5 不定詞 ① Reading 44 Grammar & Expression Writing /28 (268 words) 18 Arda Tur 8 宇宙エレベーター (イメージ) Cross Reference 12 Listening 8 Reading 29.08 People have always been fascinated by the stars. In the late 1950s, we began using 929 916 Jeriw blb rockets to explore space. Today, rockets remain the only method for space travel. However, some scientists and companies are discussing other ways to travel into space. They are even suggesting that it may be possible to build a space elevator. Such an elevator would be ideal to take people or equipment to a satellite in Earth's vs m orbit, the moon, or even Mars. They believe it would be expensive to build, but cheap oved) snosili saporio of bedes bi 2515JmT: 63 to operate. It would be 3,000 times cheaper than rocket travel, and it would also be Jodm Tolvo Station and Tokyo Joy trw 59728 safer. These are all positive reasons for trying to construct a space elevator. Obayashi Corporation is a Japanese company that built Tokyo Skytree, and improved the Golden Gate Bridge in America to protect it against 10 earthquakes. It has now promised to make a space elevator, which will allow people itsetovnoj anti mon doiniqo ono ar jedW (1) to go to a space station. Currently, the firm is researching the materials and costs. in einbiguier Obayashi Corporation wants to complete its project by 2050. Insoningie pig sabi gdT Most experts say that such a space elevator is not realistic. They also say it biq SILP 10 would be too would be too expensive. Other experts, however, think that a space elevator will be 15 built one day. It may all depend on human imagination and ambition. In fact, when in 1961 President John F. Kennedy announced the dramatic and ambitious goal to send an American rocket to the moon, many people doubted it could be done. But his goal was achieved in July, 1969, when the astronaut Neil Armstrong stepped onto the Moon's surface. ange Total ⑨25分 0:40 大意把握 SW.Y 問1 次は ア. イ. ウ I 問2 20 E て 19

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英語 高校生

英語の時制の問題なのですが、全体的に答えがわかりません。考え方でもいいので教えていただけませんか?

1. I think something wrong (happen) [4語] 「何か良くないことが起こるだろうと見 2. He (live) in Tokyo. 3. We (fly) to Vancouver on our school trip next summer. [₂] 4. It (rain ) in Osaka tomorrow. [2語] 「明日、大阪は雨です」 5. I'll call you as soon as I (arrive) at Kyoto station. 6. He (leave ) Japan next week. [進行形を使って] 7. I (read) around midnight last night. 8. I (be) a university student. 9. She (not know ) my e-mail address. 10. Please call me later. We (have) lunch. 11. Water (boil) at 100°C at sea level. 12. World War II (break) out in 1939. 13. He (teach) Japanese in this school ten years ago. 14. (I see) Ted tonight. [進行形を使って ] 15. (Ivisit) my uncle in Canada this summer. 4語 「叔父さんを訪ねる予定 (計画済み) 16. Ken (go) to school at eight. 17. The phone rang while I (cook). 18. The sun (rise) in the east. 19. Please wait here until dinner (be) ready. 20. My father (work) for a trading company. 21. Haste (make) waste. 「急がば回れ」 22. What (you do ) tonight? [5] 「今夜は何をする予定ですか?」 23. I must finish my homework before my mother (come ) home. 24. I (see) you next week. [2] 「来週君と会うよ」 25. My grandfather (be) seventy next year. 26. (I meet) Jim this evening. [*] 27. He usually (walk) slowly, but he (walk) very fast now. 28. Practice (make) perfect. (習うより慣れろ ) 29. We (fly) over Osaka around ten tonight. 10時ごろ大阪の上空を飛んでいるでし 30. If 「明日、雪がたくさん降るようなら、 電車には乗らない (take a train) 」

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英語 高校生

これといてください。至急です お願いします 英語分かるかた

2010 解答用紙を6/1(木)に提出 解説は英語でします。 【1】 次の英文を読んで、後の設問に答えよ。 (配点 50) A few years ago, a certain famous university in Japan asked a unique question as its entrance examination in English. The question was this: Write a reply in English to a junior high school student who doesn't like studying. He says he has no intention of going abroad, so he doesn't think he needs to study English. Nor does he want to get a job in which the knowledge of math or science is required. He, therefore, insists that he cannot understand the reason he is forced every day to study subjects he is not interested in. As an entrance examination, it's not very difficult to write an answer to this question. (2) you take it seriously, however, it touches on such a profound aspect of human nature that it is worth thinking about. Fundamentally, why do you have to study? What is learning for? Would you still like to study even if there were no schools or examinations in the world? In my opinion, it is possible to answer such questions from a practical and essential point of view. First, it is not rare for anyone to find changes in their own preferences or desires over time. Sometimes we find ourselves possessing no interest in what we thought to be precious before. Sometimes we are surprised to realize that what we thought to be of little value is so important. So it is quite hard, especially for young people, to predict actually what one will want in the future, say, ten years from now. That's why it is highly desirable for students to prepare for their future by increasing their knowledge and improving their intelligence. Whatever job one may get, it is quite (4) that knowledge or intelligence gets in the way. This can be demonstrated partly by many adults confessing that they should have studied harder. ( 5 ), it's only while one is young that one has a good memory and can absorb and retain a vivid impression of what one has learned. Next, I would like to talk about a more subtle viewpoint. Essentially, no human beings can be satisfied with what they already have, and everyone has, at 1921 the bottom of their heart, the desire for a better existence. Please do not interpret (67 INT this only in terms of materialism or religious belief. Of course, food, clothing. and housing are important. Still, ( 7 ). Also, in the present age, it is difficulí to feel there is anything in the belief that God will come to help you have a better existence some day. Even if all of your basic needs are met, without one important thing, you cannot feel that your life is meaningful. This one thing is the ambition to improve yourself. When you learn something you didn't know before, you will surely feel the satisfaction that no other element in life can give. In this sense, learning will enable you to broaden your world, giving you the joy of knowing. In short, learning is an important way to make your own life richer. (A) 下線 (1) (3) を和訳せよ。 (B) 空所 (2) ( 5 )に入れるのに最も適切なものを、それぞれ次のア~エ の中から1つずつ選び、 その記号を記せ。 (2) 7 Because If (5) 7 For example In conclusion Though In addition What is worse (C) 空所 (4) に入れるのに最も適切な 同じ段落の中から抜き出して、 解答欄に記入せよ。 下線部)が表す内容を、 本文に即して70字以内の日本語で説明せよ。 1931 1. Unless

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