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数学 高校生

エクササイズ6の(1)の解き方が分かりません。解説の、(b-c+c-a+a-b)xの二乗 から答えを出すまでの計算の仕方が理解できません💦なるべく丁寧に解説お願いします🙇‍♀️

HINT 直接展開するのではなく、必要な項だけを取り出して考える。 の展開式で (1)(x+3x2+2x+7)(x3+2x²-x+1) (ア) x の項は x32x2, 3x2・x である。 よって, 求める係数は 1・2+3・1=5 (イ)x3の項は x 1, 3x2・(-x), 2x+2x2, 7.x3 である。 1・1+3・(-1)+2・2+7・1=9 よって, 求める係数は (2) (2x+3y+z)(x+2y+3z)(3x+y+2z) の展開式でxyz の 項は,x,y,zを含む項をそれぞれ1つずつ掛けたときに現 れる。 これらの項は ④6 2x・2y・2z, 2x・3z•y, 3y・x・2z, 3y・3z3x, z・x・y, z2y・3x の6つであるから,xyzの係数は 8+6+6+27 +1+6=54 EX 【1) (5x)=(b−c){x²−(b+c)x+bc} +(c-a){x2-(c+a)x+ca} +(a−b){x²-(a+b)x+ab} =(b-c+c-ata-b)x2 -(b²-c²+c²-a²+a²-b²)x +bc(b-c)+ca(c-a)+ab(a-b) =a²b-ab2+b'c-bc'+ca-ca² 次の式を計算せよ。 (1) (x−b)(x−c)(b−c)+(x−c)(x−a)(c—a)+(x−a)(x−b)(a−b) (2) (x+y+2z)³—(y+2z-x)³—(2z+x−y)³—(x+y−2z)³ y+2z=A, y-2z=Bとおくと (5x)=(x+A)³-(A-x)³-(x-B)³-(x+B)³ 7 (x³ +3x²+2x+7) (x³ +2x²-x+1) =6xA2-6xB2=6x(A²-B2) =6x{(y+2z)-(y-2z)2} (x+3x²+2x+7)(x3+2x2-x+i) U ODE- ←2x+3y+zの 「2x」, x+2y+3zの 「2y」, 3x+y+2zの 「2z」 を掛けたときに現れる 2x2y2z 項は = (x+A)+(x-A)³-(x-B)³-(x+B)³ = (x³ +3x²A+3xA²+A³)+(x³−3x²A+3xA²-A³) 6+6+ (x³-3x²B+3xB²-B³)-(x³+3x²B+3xB²+B³) 77 ここから下 が分か りません←輪環の順に整理。 =6x{y'+4yz+4z²-(y^-4yz+4z")}=6x8yz=48xyz 解 y+2z=A,y-2z=B とおくと (5₁)=(x+A)³—(A-x)³-(x-B)³-(x+B)³ ={(x+A)+(x-A)*}-{(x+B)+(x−B)*} (2) 山梨学院大 】 ←x²の係数は0 ←xの係数は0 ←-(A-x)³ =-{-(x-A)} =-(-1)³(x-A)³ =(x-A)3 ←(a+b)^-(4-6) =4abと (a+b)²+(a−b) =2(+6) は記 使えるようにして

解決済み 回答数: 1
英語 高校生

仮定法のbe動詞の使い分けの説明があまりピンと来ないです。何であってもwere を使うと書いてあるのにwasを使う場合があるとはどういうことでしょうか?

if節でwereを 使う time, 確認 (3) be 動詞は were を使う If I were you, I would accept his offer.go_bolt 「もし私があなたなら」→「受けるだろう」 : 主語がIでもwereを使う Bon Jov 9vino bluoo 仮定法過去のif節でbe動詞を使う場合は, 主語が何であっても wereを使う。 if節で使う wereとwas retted ti misl の事実とは通りと か三人称単数 の場合は wasも 使う THE し…..でなければ) は, 仮定法では使わないのが原則。 Unless I have to work late, I'll see you at seven. (残業をする必要がなければ, 7時にお会いしましょう) bluow TÉ (1) If she were here, I'd give her a big hug. (もし彼女がここにいたら, 私は彼女をぎゅっと抱きしめるだろう) ただし, Ⅰ のあとや現在形でisを使う場合には was が使われること も多い。 Wouldn't it be cool if my father was Bill Gates? (お父さんがビル・ゲイツだったら、 素敵じゃない?) Wouldn't it be cool? は否定疑問文 (p.420)。 ● If there was a spin-off, I wouldn't watch it. Mode (続編があっても、私はそれを観ないだろう) この if は 「たとえ・・・でも (even if) 」 の意味 (p.649)。 仮定法過去と仮定法過去完了 389 1 仮定法

解決済み 回答数: 2
英語 中学生

3枚目の写真のような問題って どうやって解くんですか? 私はいつも段落の最初と最後を見てるんですが 一問間違えてしまいました。ぼぼ勘だったりもするので教えて欲しいです🙇‍♀️

いる。 各問いに答えよ。なお, [1] Have you ever seen the 2D codes which have a special mark on the corners? For example, you can find the 2D codes in your textbooks. When you scan them with a tablet computer, you can see pictures or watch videos. Today, a A lot of people around the world use them in many different ways. This type of (2 2D code was invented by engineers at a car parts maker in Japan. [2] When cars are produced, many kinds of parts are needed. Car parts makers have to manage all of the car parts. About 30 years ago, car companies needed to produce more kinds of cars, and car parts makers had to manage many different kinds of car parts for each car. At that time, they used barcodes to manage the car parts, but they could not put a lot of information in one barcode. So, they used many barcodes. Workers had to scan many barcodes. A worker at a car parts maker had to scan barcodes about 1,000 times a day. It took a lot of time to scan them. The 0 000742 221101 barcode (バーコード) workers needed some help to improve their situation. [3] The engineers at a car parts maker in Japan knew the situation of the workers. They started to learn about 2D codes because 2D codes can contain more information than barcodes. There were already some types of 2D codes in the U.S. One type could contain a lot of information, but it took a lot of time to scan that type. Another type was scanned very quickly, but it contained less information than other types. The engineers at the car parts maker did not use these types. They decided to create a new type of 2D code which had both of those good points. The engineers needed a long time to create this new type which could be scanned quickly. Finally, they thought of an idea. They thought, "If a 2D code has a special mark on the three corners, it can be scanned very quickly from every angle." In this way, the new type of 2D code with special marks was invented by the engineers at a car parts maker in Japan. 2D code

未解決 回答数: 1