Đáp án:
${a,x=}$ $\dfrac{1}{6}$
${b,x=}$ $\dfrac{2}{5}$
${c,x=}$ $-\dfrac{59}{140}$
Giải thích các bước giải:
${a,}$ $-\dfrac{2}{15}-x=$ $-\dfrac{3}{10}$
${x=}$ $-\dfrac{2}{15}-$ $(-\dfrac{3}{10})$
${x=}$ $-\dfrac{2}{15}+$ $\dfrac{3}{10}$
${x=}$ $\dfrac{1}{6}$
${b,x+}$ $\dfrac{1}{3}=$ $\dfrac{2}{5}-$ $(-\dfrac{1}{3})$
${x+}$ $\dfrac{1}{3}=$ $\dfrac{2}{5}+$ $\dfrac{1}{3}$
${x+}$ $\dfrac{1}{3}=$ $\dfrac{11}{15}$
${x=}$ $\dfrac{11}{15}-$ $\dfrac{1}{3}$
${x=}$ $\dfrac{2}{5}$
${c,}$ $\dfrac{3}{7}-x=$ $\dfrac{1}{4}-$ $(-\dfrac{3}{5})$
$\dfrac{3}{7}-x=$ $\dfrac{1}{4}+$ $\dfrac{3}{5}$
$\dfrac{3}{7}-x=$ $\dfrac{17}{20}$
${x=}$ $\dfrac{3}{7}-$ $\dfrac{17}{20}$
${x=}$ $-\dfrac{59}{140}$
~Xin hay nhất~
