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数学 高校生

この問題の⑶番を教えてください。 途中式でなぜ−4abになるかわかりません。 解説お願いします。

なお,対称式の計算において, 次の式変形はよく出てくるから覚えておこう。 であるが,これを直接代入して計算する a'+B"=(α+B)°-2aB, α'+B"=(α+B)-3aB(α+B), (α-8)"=(α+B)'ド 74 基礎例題 41 2つの解の対称式の値 2次方程式 xー3x+4=0 の2つの解をα. Bとするとき, 火の式の値を めよ。 基礎例題 42 1 )2 B (2) α+8° GHART Q GUIDE) α+8, aB で表す 解と係数の関係を利用 1 解と係数の関係により, α+8, aBの値を求める。 2 与えられた式を α+B, aBで表す。 3 1で求めた値を代入して計算する。 2次方程式の解 a, Bの対称式 1つの ことが一 解と保 -a+8=-, ag= すなわ 田解答田 解と係数の関係から α+B=3, aB=4 口(1) α+8°= (α+B)°-2αB=3°-2·4=1 (α+B)°-3cB(α+B) =3°-3·4-3=19 (2) [別解] (2) α- °+8°=(a+B)(α-aB+ 0から =3(1-4)=-9 また。 日(③ ( (-)= (α-A_ (a+B)ー4cB (aB)° これを 1 \2 1 1 ーまず, 1 を通分する。 aB (aB)° B したか。 3-4-4 7 4° 16 Lecture α, Bの対称式の計算 であっ 一般に,数値を代入して式の値を求めるときは, 少しでも計算がらくになるように進か 上の例題の場合, 2次方程式の解は x= 3土、7i さー 2 は,大変めんどうである。 式の値 また。 計算はらくに 式を変形してから代入 この ただ な +=(α+B°-2aB, α"+B"=(α+B)°-3c8(α+8). (α-B}=(α+Bl| A9の り.2 ふを 20c

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英語 高校生

Power on 2のLesson 6です!写真が本文なのですが、Part 3にはいくつの長所が書かれてますか?

Tas Lesson6 Vegetable Factories 予習プリント PAF Task-1: Translate underlined parts into Japanese C C PART 1 Takumi: Angelina, have you ever heard of vegetable factories? I learned about them for the first time on TV last night. Such factories were first built in Denmark in 1957, and similar factories were PAI also introduced in the US in the 1970s. Angelina: Vegetable factories-yes, 1 know about them, too. In Japan, they were first built in the early 1980s to produce kaiware sprouts. These factories are now attracting much attention as a new type of agriculture I hear new vegetables like frilice lettuce and ice plant are being produced there. Takumi: Wow! You really knowa lot about vegetable factories. Angelina: Would you like to know more? Takumi: Definitely! もちろみ に C フリルレタズ C PA C C C PART 2 C You may be surprised to hear that we can grow vegetables without the sun and soil. But that is what people do in vegetable factories. In these factories, electric light and fertilized water are used instead of the sun and soil. Temperature and humidity are also controlled. It seems that limited space in vegetable factories is not a big problem. Workers fully use the space by stacking shelves of vegetables. Actually, you can find small vegetable factories in the previolisly wasted space of office buildings or restaurants. At present, the main crops from vegetable factories are leaf vegetables. But in the near future, PA C C Ta more varieties of vegetables are sure to come. し]必ず…する PART 3 What are the good points of vegetable factories compared to traditional agriculture? For one thing, they can provide a stable supply of vegetables, even in bad weather conditions. For another thing, vegetables grow much faster in a controlled environment. Other good points include no use of chemicals and good taste with more vitamins. Unfortunately, vegetable factories still face one challenge. Running them requires a lot of money. Because of this cost, these vegetables are expensive to buy. Hopefully, in the near future, we will have solved this problem. うまくいけば PART 4 文に、科に Talkumi: Agriculture without the sun and soil. Hmm. That's a great idea indeed. Honestly, Ive got a bit of, ahem, “agriculture shock" from what you've just told me in a good way though. Angelina: Ha-hal Have you? Good. If we can develop vegetable factories on a large scale, we may be able to solve the problem of food shortages. Takumi: Yeah, I agree. And the way we view vegetables may change whether we like it or not. Oh, by the way, Angelina, culture and agriculture are closely related, as you can see from the words. Agri-means “farming," and culture means “to grow something." Angelina: Oh, so you're giving alecture now! 422words

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