\(S=\dfrac{27+4500+135+550.2}{2+4+6+...+14+16+18}\)

\(S=\dfrac{4527+135+1100}{\left(2+18\right).9.2}\)

\(S=\dfrac{4662+1100}{20.9.2}\)

\(S=\dfrac{5762}{90}\)

\(S=\dfrac{2881}{45}\)

`S=(27+4500+135+550.2)/(2+4+6+…+14+16+18)`

`S=(27+4500+135+1100)/((2+18)+(4+16)+…+(8+12)+10)`

`S=((27+135)+(4500+1100))/(20+20+…+20+10)` `(`Có `4` số hạng `20)`

`S=(162+5600)/(20.4+10)`

`S=5762/90`

`S=2881/45`

\(S=\frac{27+4500+135+550.2}{2+4+6+...+14+16+18}\)

\(S=\frac{4527+135+1100}{\left(2+18\right).9:2}=\frac{4662+1100}{20.9:2}=\frac{5762}{90}=\frac{2881}{45}\)

\(B=\frac{27+4500+135+1100}{\frac{\left(2+18\right).9}{2}}=\frac{5762}{10.9}=\frac{2881}{45}\)

2881/45

- Mình dùng cách lớp 8 để làm câu b được không :)?

- Tham khảo câu b:

https://olm.vn/hoi-dap/tim-kiem?q=+++++++++++A=2006%5E2005+1/2006%5E2006+1B=2006%5E2006+1/2006%5E2007+1so+s%C3%A1nh+A+v%C3%A0+B&id=520258

:< dễ lém á , mng giúp mìn ii 

\(\frac{27+4500+135+550.2}{2+4+6+...+16+18}\)= \(\frac{27+4500+135+1100}{\left(18+2\right).\left[\left(18-2\right):2+1\right]:2}\)=  \(\frac{5762}{20.19:2}\)=\(\frac{5762}{190}\)=\(\frac{2881}{95}\)

Xét tử số:

27.4500+135.550.2=27.4500+27.5.550.2=27.4500+27.5500=27.10000=270000

Xét mẫu số:

2+4+6+...+16+18

Ta thấy:dãy số này có QLC=2.

=>SSH là:(18-2):2+1=9(số)

=>Tổng là:(2+18).9:2=90.

Vậy ps cần tìm là:270000/90=3000

Cho A=3\(^1\)+3\(^2\)+...+3\(^{2006}\)

a)Rút gọn A

b)Tìm x để 2A+3=3\(^x\)

2, 

a) \(315-\left(135-x\right)=215\)

\(\Rightarrow135-x=315-215\)

\(\Rightarrow135-x=100\)

\(\Rightarrow x=135-100\)

\(\Rightarrow x=35\)

b) \(x-320:32=25\cdot16\)

\(\Rightarrow x-10=5^2\cdot4^2\)

\(\Rightarrow x-10=20^2\)

\(\Rightarrow x-10=400\)

\(\Rightarrow x=410\)

c) \(3\cdot x-2018:2=23\)

\(=3\cdot x-1009=23\)

\(\Rightarrow3\cdot x=1032\)

\(\Rightarrow x=1032:3\)

\(\Rightarrow x=344\)

d) \(280-9\cdot x-x=80\)

\(\Rightarrow280-x\cdot\left(9+1\right)=80\)

\(\Rightarrow280-10\cdot x=80\)

\(\Rightarrow10\cdot x=280-80\)

\(\Rightarrow10\cdot x=200\)

\(\Rightarrow x=20\)

e) \(38\cdot x-12\cdot x-x\cdot16=40\)

\(\Rightarrow x\cdot\left(38-12-16\right)=40\)

\(\Rightarrow x\cdot10=40\)

\(\Rightarrow x=40:10\)

\(\Rightarrow x=4\)

bài 1 cậu ko giải giúp mình dc à