\(\dfrac{n+5}{n+2}=1+\dfrac{3}{n+2}\)

Để \(\dfrac{3}{n+2}\) ∈ Z

⇒  \(\left(n+2\right)\text{∈}Ư\left(3\right)=\left\{1;-1;-3;3\right\}\) 

⇒ \(n\text{∈}\left\{-1;1;-3;-5\right\}\)

a: \(-\dfrac{6}{13}=-\dfrac{12}{26}=\dfrac{-18}{39}=-\dfrac{24}{52}=\dfrac{-30}{65}=\dfrac{-36}{78}=\dfrac{-42}{91}\)

b: \(\dfrac{15}{-7}=\dfrac{-15}{7}=\dfrac{-30}{14}=\dfrac{-45}{21}=\dfrac{-60}{28}=\dfrac{-75}{35}=-\dfrac{90}{42}\)

e,\(3\frac{2}{7}x-\frac{1}{8}=2\frac{3}{4}\)

\(=>\frac{23}{7}x-\frac{1}{8}=\frac{11}{4}\)

\(=>\frac{23}{7}x=\frac{11}{4}+\frac{1}{8}=\frac{23}{8}\)

\(=>x=\frac{23}{8}:\frac{23}{7}\)

\(=>x=\frac{7}{8}\)

b) 5 và 4/7 :x=13

  39/7 :x =13

          x= 39/7 :13

         x= 3/7

đây nhá có gì thắc mắc hỏi chị nhá

b) \(5\frac{1}{4}.\frac{3}{8}+10\frac{3}{4}.\frac{3}{8}\)

\(=\left(5\frac{1}{4}+10\frac{3}{4}\right).\frac{3}{8}\)

\(=16.\frac{3}{8}=6\)

c) \(6\frac{1}{5}.\frac{-2}{7}+14\frac{4}{5}.\frac{-2}{7}\)

\(=\left(6\frac{1}{5}+14\frac{4}{5}\right).\frac{-2}{7}\)

\(=21.\frac{-2}{7}=-6\)

a) Ư(60):{ 1;2;3;4;5;6;10;12;15;20;30;60}

    Ư(84):{ 1;2;4;6;7;12;14;21;42;84}

    Ư(120):{ 1;2;3;4;5;6;8;10;12;15;20;24;30;40;60;120}

ƯC(60;84;120):{ 2;4;6;12}

nhưng vì x_> 6 nên x = 2,4,6

nhiều quá bạn ơi ko nhanh được đâu