Tìm x: a/ 1/15 – x = 3/10 b/ 5/12 + 5/x -1/8=1/2 c/ 4/10 – x = -3/20 + 3/5

Đáp án:

Giải thích các bước giải:

a) $\frac{1}{15}$ – x = $\frac{3}{10}$

=> x= $\frac{1}{15}$ – $\frac{3}{10}$

=> x = $\frac{-7}{30}$

Vậy x =$\frac{-7}{30}$

b)$\frac{5}{12}$ + $\frac{5}{x}$ – $\frac{1}{8}$ = $\frac{1}{2}$

=> $\frac{5}{12}$ + $\frac{5}{x}$ = $\frac{1}{2}$ + $\frac{1}{8}$

=> $\frac{5}{12}$ + $\frac{5}{x}$ = $\frac{5}{8}$

=> $\frac{5}{x}$ = $\frac{5}{12}$ – $\frac{5}{8}$

=> $\frac{5}{x}$ = $\frac{-5}{24}$

=> -5x = 5 . 24

=> -5x = 100

=> x = 20

Vậy x = 20

c) $\frac{4}{10}$ – x = $\frac{-3}{20}$ + $\frac{3}{5}$

=> $\frac{4}{10}$ – x = $\frac{9}{20}$

=> x = $\frac{4}{10}$ – $\frac{9}{20}$

=> x = $\frac{-1}{20}$

Vậy x = $\frac{-1}{20}$