một ô tô đi trên quãng đường AB vs vận tốc 40km/h.Nếu tăng vận tốc thêm 10km/h thì ô tô đến B SỚM HƠN DỰ ĐỊNH 15 phút .quãng đường bằng mấy
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19 tháng 12 2020
5^333 = ( 5^3 ) ^111 = 125^111
4^555 = ( 4^5 ) ^111 = 1024^111
Vì 1024 > 125 nên 5^333 < 4^555
2^400 = ( 2^2 )^200 = 4^200
Vậy 2^400 = 4^200
10^30 = ( 10^3 )^10 = 100^10
2^100 = ( 2^10 )^10 = 1024^10
Vì 1024 > 100 nên 10^30 < 2^100
5^40 = ( 5^4 )^10 = 625^10
Vì 625 > 620 nên 5^40 > 620^10
10 tháng 12 2020
\(P=\frac{1}{x^2-x+1}+1-\frac{x^2+2}{x^3+1}\)
\(\Rightarrow P=\frac{1}{x^2-x+1}+1-\frac{x^2+2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{1\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}+\frac{1\left(x+1\right)\left(x^2-x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}-\frac{x^2+2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{1\left(x+1\right)+1\left(x+1\right)\left(x^2-x+1\right)-x^2-2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{x+1+1\left(x^3+1\right)-x^2-2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{x+1+x^3+1-x^2-2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{x+x^3-x^2}{\left(x+1\right)\left(x^2-x+1\right)}=\frac{x\left(1+x^2-x\right)}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(\Rightarrow P=\frac{x\left(x^2-x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}=\frac{x}{x+1}\)
28 tháng 4 2017
mk mới học nên ko giúp đc gì, mong bạn thông cảm, chúc bạn học thật giỏi
PT
9 tháng 12 2020
Rearrange the words and phrases to make meaningful sentences
1. an/pagoda/village/old/my/has.
- > My village has an old pagoda.
2.railway-station/not/small/a/that/town/has/got.
-> That town has not got a small railway- station.
3.one/Mr and Mrs. Brown/only/have/car/got.
-> Mr and Mrs Brown only have got one car.
4.building/school/new/has got/my/a.
-> My school has got a new building.
5.many/got/city/lakes/that/has/beautiful
-> That city has got many beautiful lakes.
6.Lodon/parks/has/famous/got/many
-> London has got many famous parks
7.any/city/museums/your/has/got?
-> Has your city got any museums?
8.art galleries/not/town/has/got/this/any
-> This town has not got any art galleries.
9.building/old/got/Hue/pagodas/and/many/has
-> Hue has got many old buildings and pagodas.
10.a/house/has/got/garage/your?
-> Has your house got a garage?
11 tháng 12 2020
1. an/ pagoda/ village/old/ my has.
=> My village has an old pagoda.
2. railway-station/ not/small/ a/ that/ town/ has/ got.
=> That town has not got a small railway-station
3. one/ Mr. and Mrs. Brown/ only/ have/ car/ got.
=> Mr. and Mrs.Brown only have got one car.
4.building/ school/ new/ has got/ my/ a.
=> My new school has got a new building.
5. many/ got/ city/ lakes/ that/ has/ beautiful.
=> That city has got many beautiful lakes.
6. London/ park/ has/ famous/ got/ many
=> London has got many famous park.
7. any/ city/ museums/ your/ has/ got?
=> Has any museums in your city?
8. art gallaries/ not/ town/ has/ got/ this/ any
=>This town has not got any art gallaries.
9. buildings/ old/ got/ Hue/ pagodas/ and/ many/ has
=> Hue has got many old buildings and pagodas.
10. a/ house/ has/ got/ garage/ your?
=> Has your house got a garage?
15 phút = 1/4 giờ
Đặt quãng đường AB là S ta có
\(\frac{S}{40}-\frac{S}{50}=\frac{1}{4}\Rightarrow S=50\)
Quãng đường AB dài 50km