Cho biết x + 2/15 = -3/10 thì: A. x = -13/30; B. x = 11/30; C. x = -5/150

2/15

Cho biết \({\rm{x + }}\frac{2}{{15}}{\rm{ = }} - {\rm{ }}\frac{3}{{10}}\) thì:

\({\rm{x = }}\frac{{ - {\rm{ 13}}}}{{30}};\)

\({\rm{x = }}\frac{{11}}{{30}};\)

\({\rm{x = }}\frac{{ - {\rm{ }}5}}{{150}};\)

\({\rm{x = }}\frac{{65}}{{150}}.\)

Giải thích

Đáp án đúng là: A

Ta có: \(x{\rm{ + }}\frac{2}{{15}}{\rm{ = }} - {\rm{ }}\frac{3}{{10}}\)

\(x{\rm{ = }} - {\rm{ }}\frac{3}{{10}}{\rm{ }} - {\rm{ }}\frac{2}{{15}}\)

\(x{\rm{ = }}\frac{{ - {\rm{ 9}}}}{{30}}{\rm{ }} - {\rm{ }}\frac{4}{{30}}\)

\(x{\rm{ = }}\frac{{ - {\rm{ 9 }} - {\rm{ 4}}}}{{30}}\)

\(x{\rm{ = }}\frac{{ - {\rm{ 13}}}}{{30}}.\)

Vậy \({\rm{x = }}\frac{{ - {\rm{ 13}}}}{{30}}.\)