Có $\frac{a}{b}=\frac{2}{5}$
=> $5a=2b$
=> $5ab=2b^{2}$
<=> $200= 2b^{2}$
<=> $b^{2}=100$
<=> $b=-10$ (vì a< 0 mà ab >0 => b <0)
=> $a=-4$
Có $a-b=-4-10=-14$
Ta có :
$\frac{a}{b}$ =$\frac{2}{5}$ ⇒$\frac{a}{5}$ =$\frac{b}{2}$
Đặt : $\frac{a}{5}$ =$\frac{b}{2}$ = k
⇔ a = 5k
b = 2k
a . b = 40
⇒ 5k . 2k = 40
⇒ 10$k^{2}$ = 40
⇒ $k^{2}$ = 4 ( vì a<0 và a.b>0 ⇒ b<0)
⇒ k = -2
Với k = -4 thì a = -10 , b=-4
Gía trị a - b = -10 - 4= -14
phân tích thành nhân tử (2a+b)^2-(2b+a)^2
giải phương trình $\sqrt[]{x}$ + $\sqrt[]{4-x}$ = $\sqrt[]{5+ 4x- x^{2}}$
II-Choose the best answer for each of 1-The government has sent...aid to the refugees. A-human D-humanity C-humanitarian B-humane 2-“Are you singer or married?" is to ask about one's...... A-occupation 3-When he graduated from university he got his A-diploma 4-“....do you borrow this science book?" -"To read more about Marie Curie's life". A-what D-nationality C-address B-marital status ....... D-bachelor B-certificate C-degree D-which C-when B-why 5-She likes her children....to the dentist every six months. A-go 6-We were not hungry. We ....a big breakfast. A-just had 7-Please don't....to stamp on the letter I gave you to post. A-remind C-going D-to going B-to go B-have just had C-were just having D-had just had B-realize C-forget D-remember 8-He will ring up when he.......in Paris. A-arrives 9-Your windows need....at least once a year. A-cleaning 10-I.. .much better after I.... A-felt/had taken 11-It was raining hard, so we decided A-not going 12-My little daughter....whenever she ...sad movies. A-is crying/sees 13-I finally finished .......at seven and served dinner. A-cooking 14-By the time he reached the dentist's ,the pain in his tooth........ A-stops 15-It....him 30 minutes ......to school every morning. B-will arrive C-arrived D-would arrive C-being cleaned .the medicine. B-to clean D-have cleaned B-felt/took C-had felt/took D-had felt/had taken ..... B-not to go C-to not go D-not go B-cried/sees C-cries/sees D-cries/saw B-to cook C-being cooked D-to be cooked B-was stopping C-had stopped D-has stopped B-took /walked 16-She received... .the airport.......exactly 5 o'clock. A-take/to walk C-takes/walk D-takes/to walk A-in/at B-at/at C-at/in D-in/in
Hãy giái thích cho mình hiểu tại sao lại ra là( t²-4t+3) .cảm ơn nhiều ạ
2 1 after / Peter / match / tired /Was / the A Was Peter tired after the match? B Yes, he was. 2 you/ night/Where / last/ were A where B I was at home. 3 they / concert/ late/ the /Were / for B No, they weren't. 4 did / land / the / Where / plane A B At the airport. 5 did / college / your / in / brother / What / study B Biology. 6 Was / tall / boyfriend / very / your / first A B No, not really. 7 didn't / the / you / wait / Why / for / bus A B Because it was too cold. 8 time / work / did /What / arrive / Sandra / yesterday /a
Nhờ mn giải giúp mik với ạ, trình bày cách giải mik với luôn. Cảm ơn nhiều
Mọi người giúp em cái này ạ. Em xin cảm ơn trước Giải nhanh giúp mình ạ
Các bn tìm a,b giúp mk với ak ! Các bn có thể lm ra 1 quyển nháp rùi các bn chụp cho mk ak ! Mk cảm ơn ak !
Viết 1 đoạn văn ngắn tưởng tượng Mị Châu và Trọng Thủy gặp nhau sau khi chết. Giúp em vs huhu :((
trong 2 bức chân dung thuý vân và thuý kiều em thấy bức chân dung nào nổi bật hơn . vì sao?
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