Người ta nói rằng: những hạt rơi chậm thường được gió mang đi xa hơn là vì những hạt rơi chậm thì có thời gian bay ở trong không trung dài hơn, nên được gió đưa đi xa hơn.

than bạn ạ

tick mình nhé bạn trong danh sách

Ta có: A=1.2+2.3+3.4+4.5+..............+100.101

B=1.3+2.4+3.5+4.6+...............+100.102

Vậy A-B=(1.2+2.3+3.4+4.5+..............+100.101)-(1.3+2.4+3.5+4.6+...............+100.102)

=(1.2-1.3)+(2.3-2.4)+(3.4-3.5)+(4.5-4.6)+..........+(100.101-100.102)

=(-1)+(-2)+(-3)+(-4)+..........+(-100)

=-(1+2+3+4+.........+100) có (100-1)+1=100 số hạng

=\(-\left[\left(100+1\right).100:2\right]\)

=-5050

Chúc bạn học tốt!

1. It usually rains.................. in Central Viet Nam than in other regions.(heavy)

\(\Rightarrow\) It usually rains more heavily in Central Viet Nam than in other regions

2.I will have to try a bit........................ than this. (hard)

\(\Rightarrow\)I will have to try a bit harder than this.

3.The hall was lighted.............................than the corridors.(bright)

\(\Rightarrow\)The hall was lighted more brightly than the corridors.

4.Times goes by.......................................when we are busy.(quick)

\(\Rightarrow\)Times goes by more quickly when we are busy.

5.Our family has lived............................in the country than in the town since last year.(happy)

\(\Rightarrow\)Our family has lived more happily in the country than in the town since last year.

6.The boys were playing the game..................................than the girls.(noisy)

\(\Rightarrow\)6.The boys were playing the game more noisily than the girls.

1. Villagers/usually/living/farming/raising animals/ making handicrafts.

\(\Rightarrow\) Villagers usually earn their living from farming, raising animals, and making handicrafts.

2. They/live/a small community/a temple/where great evens/such as/festivals/organized.

\(\Rightarrow\) They live in a small community with a temple where great events such as festivals are organized.

3.Along/coastal lines/fisherman/depend/sea/live on.

\(\Rightarrow\) Along the coastal lines, fishermen depend on the sea to live on.

Chúc bạn học tốt!

\(\frac{1}{19}+\frac{9}{19.29}+\frac{9}{29.39}+....+\frac{9}{1999.2009}\)

=\(\frac{1}{19}+\frac{1}{10}.\left(\frac{9}{19}-\frac{9}{29}+\frac{9}{29}-\frac{9}{39}+....+\frac{9}{1999}-\frac{9}{2009}\right)\)

=\(\frac{1}{19}+\frac{1}{10}.\left(\frac{9}{19}-\frac{9}{2009}\right)\)

=\(\frac{1}{19}+\frac{1791}{38171}\)

=\(\frac{200}{2009}\)

Bạn tham khảo nha:

M=x²y-xy²-5x+5y-12

M=xy(x-y)-(5x-5y)-12

M=5(x-y)-5(x-y)-12

M=0-12

M=-12

Chúc bạn học tốt nha!

S=\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+......+\frac{1}{95.97}+\frac{1}{97.99}\)

S=\(\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+.......+\frac{1}{97}-\frac{1}{99}\right)\)

S=\(\frac{1}{2}.\left(1-\frac{1}{99}\right)\)

S=\(\frac{1}{2}.\frac{98}{99}\)

S=\(\frac{49}{99}\)

tớ làm ít thui:

a. 201²=(200+1)²=200²+2.200+1+1²=40000+400+1=40401

b. 37.43=(40-3)(40+3)=40²-3²=1600-9=1591

c.37²+37.26+13²=37²+2.37.13+13²=(37+13)²=50²=2500

Ta có:

\(\frac{43}{30}=1+\frac{13}{30}=1+\frac{1}{\frac{30}{13}}=1+\frac{1}{2+\frac{4}{13}}=1+\frac{1}{2+\frac{1}{\frac{13}{4}}}=1+\frac{1}{2+\frac{1}{3+\frac{1}{4}}}\)

Thay vào x,y,z vậy x=2;y=3;z=4

Chúc bạn học tốt!