\(5n+22⋮n+3\\ \Leftrightarrow5n+15+7⋮n+3\\ \Leftrightarrow7⋮n+3\text{ }\left(\text{Vì 5n + 14 ⋮ n + 3}\right)\\ \Leftrightarrow n+3\inƯ\left(7\right)=\left\{\pm1;\pm7\right\}\)

\(\Leftrightarrow\left[{}\begin{matrix}n+3=1\\n+3=-1\\n+3=7\\n+3=-7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}n=-2\\n=-4\\n=4\\n=-10\end{matrix}\right.\)

Vậy \(n\in\left\{-2;-4;4;-10\right\}\)

Cái dấu cộng thứ 2 phải là: Nếu x - 2 = -4 => x = -2 chứ không phải là 0 đâu nha, sorry bn

\(\left(x-2\right)^2=16\\ \left(x-2\right)^2=\left(\pm4\right)^2\\ x-2=\pm4\\ +Nếu\text{ }x-2=4\text{ }\Rightarrow\text{ }x=6\\ +Nếu\text{ }x-2=-4\text{ }\text{ }\Rightarrow\text{ }x=0\\ Vậy\text{ }x\in\left\{0;6\right\}\)

\(\dfrac{-2}{3}+\left(-0,6\right)-\dfrac{7}{10}\\ =\dfrac{-2}{3}-\dfrac{6}{10}-\dfrac{7}{10}\\ \dfrac{-20}{30}-\dfrac{18}{30}-\dfrac{21}{30}=\dfrac{-38}{30}-\dfrac{21}{30}=\dfrac{-59}{30}\)

5. Which does she like doing in her free time? => What

6. He always does the piano in the morning. => plays

1. I often watch TV at my free time. => in

2. He like surfing the Internet every day. => likes

3. He goes usually swimming on Sunday. => usually goes

4. They likes reading stories. => like

10. Does Mai always help her mother with the cooking? (always)

I never play table tennis in the afternoon. (never)

3. . She does her homework in the evening.  (usually)

=> She usually does her homework in the evening

\(SSH\text{ }của\text{ }dãy\text{ }số\text{ }là:\text{ }\dfrac{271-1}{1}+1=271\left(SSH\right)\)

Vậy số số hạng của dãy 1; 2; 3; 4; ... ; 271 là \(271\) số số hạng.