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Dien h hinh chu nhat thu 1la

15,2x9,5=144,4

chieu dai hinh 2 la

144,4:10=14,44

Chu vi hinh 2 la

(14,44+10)x2=48,88

Dap so.....

Rewrite each of the following sentences so that it means the same as the first one, beginning with the given words.

1.What an excellent girl!

--> How excellent the girl is !

2.Vietnamese students have fewer vacations than American ones.

--> American students have more vacations than Vietnam ones.

3.I never saw the sharks before.

--> This is the first time i have seen the sharks.

4.Anny drives a taxi dangerously.

--> Anny is a dangerous taxi driver.

5.It is not necesssary for your team to complete all tasks

--> Your team don't have to complete all tasks.

52x 6=312

9 phần tử nhe

em học lớp 5 

đặt B=1²+2²+3²+.....+100²

B=1+2(1+1)+3(2+1)+...+99(98+1)+100(99+1)

B=1+1.2+2+2.3+3+...+98.99+99+99.100+100

B=(1.2+2.3+...+99.100)+(1+2+3+...+99+100)

B=333300+5050

B=338050

Bài 2 :

a, \(\frac{1-5x}{x-1}\ge1\)

\(\Leftrightarrow\frac{1-5x}{x-1}\ge\frac{x-1}{x-1}\)

\(\Rightarrow1-5x\ge x-1\)

\(\Leftrightarrow-5x-x\ge-1-1\)

\(\Leftrightarrow-6x\ge-2\)

\(\Leftrightarrow x\le\frac{1}{3}\)

Vậy nghiệm của bất phương trình là \(x\le\frac{1}{3}\).

b, \(\frac{x}{x-2}-\frac{2}{x-3}>1\)

\(\Leftrightarrow\frac{x^2-3x}{x^2-5x+6}-\frac{2x-4}{x^2-5x+6}>\frac{x^2-5x+6}{x^2-5x+6}\)

\(\Rightarrow x^2-3x-2x+4>x^2-5x+6\)

\(\Leftrightarrow x^2-3x-2x-x^2+5x>6-4\)

\(\Leftrightarrow0>2\) ( vô lí )

Vậy bất phương trình vô nghiệm.

Tổng số đã bán và lần đầu là

    92+8=100(cái)

           ĐS 100 cái