tìm x 2x - 11/7 =13/3 2/3 - (- 1/2 - x) = - 4/5 11/12 - (2/5 +x)= 2/3

Câu hỏi: tìm x 2x - $\frac{11}{7}$ = $\frac{13}{3}$ $\frac{2}{3}$ - (- $\frac{1}{2}$ - x) = - $\frac{4}{5}$ $\frac{11}{12}$ - ($\frac{2}{5}$ + x) = $\frac{2}{3}$. Vui lòng lập luận từng bước. Câu trả lời: 2x - $\frac{11}{7}$ = $\frac{13}{3}$ 2x = $\frac{13}{3}$ + $\frac{11}{7}$ 2x = $\frac{13 × 7}{3 × 7}$ + $\frac{11 × 3}{7 × 3}$ 2x = $\frac{91}{21}$ + $\frac{33}{21}$ 2x = $\frac{91 + 33}{21}$ 2x = $\frac{124}{21}$ x = $\frac{124}{21}$ : 2 x = $\frac{124}{21}$ × $\frac{1}{2}$ x = $\frac{124}{42}$ x = $\frac{62}{21}$ $\frac{2}{3}$ - (- $\frac{1}{2}$ - x) = - $\frac{4}{5}$ $\frac{2}{3}$ - (- $\frac{1}{2}$) - x = - $\frac{4}{5}$ $\frac{2}{3}$ + $\frac{1}{2}$ - x = - $\frac{4}{5}$ $\frac{2 × 2}{3 × 2}$ + $\frac{1 × 3}{2 × 3}$ - x = - $\frac{4}{5}$ $\frac{4}{6}$ + $\frac{3}{6}$ - x = - $\frac{4}{5}$ $\frac{7}{6}$ - x = - $\frac{4}{5}$ $\frac{7}{6}$ + $\frac{4}{5}$ = x $\frac{7 × 5}{6 × 5}$ + $\frac{4 × 6}{5 × 6}$ = x $\frac{35}{30}$ + $\frac{24}{30}$ = x $\frac{59}{30}$ = x x = $\frac{59}{30}$ $\frac{11}{12}$ - ($\frac{2}{5}$ + x) = $\frac{2}{3}$ $\frac{11}{12}$ - $\frac{2}{5}$ - x = $\frac{2}{3}$ $\frac{11 × 5}{12 × 5}$ - $\frac{2 × 12}{5 × 12}$ - x = $\frac{2}{3}$ $\frac{55}{60}$ - $\frac{24}{60}$ - x = $\frac{2}{3}$ $\frac{31}{60}$ - x = $\frac{2}{3}$ $\frac{31}{60}$ - $\frac{2}{3}$ = x $\frac{31}{60}$ - $\frac{2 × 20}{3 × 20}$ = x $\frac{31}{60}$ - $\frac{40}{60}$ = x $\frac{-9}{60}$ = x x = $\frac{-9}{60}$ x = $\frac{-3}{20}$