Tìm x biết: 1 5/6 + x = 7/3

Giải SBT Toán 6 Bài 7: Hỗn số

Bài 4 trang 32 SBT Toán 6 Tập 2:

a) $1\frac{5}{6}+\mathrm{x}=\frac{7}{3}$;

b) $\mathrm{x}-\frac{3}{-2}=3\frac{4}{5}$;

c) $\mathrm{x}:\frac{3}{-5}=3\frac{1}{2}$;

d) $2\frac{1}{6}.\mathrm{x}=\frac{-2}{5}$.

Lời giải:

a)

$1\frac{5}{6}+\mathrm{x}=\frac{7}{3}\mathrm{x}=\frac{7}{3}-1\frac{5}{6}\mathrm{x}=\frac{7}{3}-\frac{11}{6}\mathrm{x}=\frac{14}{6}-\frac{11}{6}\mathrm{x}=\frac{3}{6}\mathrm{x}=\frac{1}{2}$

Vậy $\mathrm{x}=\frac{1}{2}$.

b)

$\mathrm{x}-\frac{3}{-2}=3\frac{4}{5}\mathrm{x}=3\frac{4}{5}+\frac{3}{-2}\mathrm{x}=\frac{19}{5}+\frac{3}{-2}\mathrm{x}=\frac{38}{10}+\frac{-15}{10}\mathrm{x}=\frac{23}{10}$

Vậy $\text{x=}\frac{23}{10}$.

c)

$\mathrm{x}:\frac{3}{-5}=3\frac{1}{2}\mathrm{x}=3\frac{1}{2}.\frac{3}{-5}\mathrm{x}=\frac{7}{2}.\frac{3}{-5}\mathrm{x}=\frac{-21}{10}$

Vậy $\mathrm{x}=\frac{-21}{10}$.

d)

$2\frac{1}{6}.\mathrm{x}=\frac{-2}{5}\mathrm{x}=\frac{-2}{5}:2\frac{1}{6}\mathrm{x}=\frac{-2}{5}:\frac{13}{6}\mathrm{x}=\frac{-2}{5}.\frac{6}{13}\mathrm{x}=\frac{-12}{65}$

Vậy $\mathrm{x}=\frac{-12}{65}$.