\(18\times85+15\times18-18\times90\)

\(=18\times\left(85+15-90\right)\)

\(=18\times10\)

`= 180`

Ko chac lamws dou ai thay mik sai nhows nhawcs nha```

`3400 + 340 + 34`\(=3774\)

Ba nghin bay tram bay muoi tu 

`---`

`x + 3 + 6 + 12 + 24 + 48 + 96 + 100 ` \(=8323\)

`x +`\(\left(3+6+12+24+48+96+100\right)=8323\)

`x +` \(\left(6+24\right)+\left(12+48\right)+\left(96+100+3\right)=8323\)

`x ` \(+30+60+199=8323\)

\(x+289=8323\)

\(x=8323-289\)

`x`\(=8034\)

`;-;:(((~~~`

\(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+...+\dfrac{1}{132}\)

\(=\dfrac{1}{1\times2}+\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+...+\dfrac{1}{11\times12}\)

\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{11}-\dfrac{1}{12}\)

\(=1-\dfrac{1}{12}\)

\(=\dfrac{11}{12}\)

\(\dfrac{2^3.3^5-4.3^4}{4^4.5^2-2^7.5}\)

\(=\dfrac{2^3.3^5-2^2.3^4}{(2^{2^4}).5^2-2^7.5}\)

\(=\dfrac{2^3.3^5-2^2.3^4}{2^8.5^2-2^7.5}\)

\(=\dfrac{1.3^5-1.3^4}{2^5.5^2-2^5.5}\)

\(=\dfrac{1.(3^5-3^4)}{2^5.(5^2-5)}\)

\(=\dfrac{1.162}{1.20}\)

\(=\dfrac{81}{10}\)

\(\text{140-180(47-90+43)+7}\)

\(=140-180.0+7\)

\(=140-0+7\)

\(=147\)

\(16x+40=120\)

\(16x=120-40\)

\(16x=80\)

\(x=80:16\)

\(x=5\)

Vậy...

Ko