Đáp án:
a ) Ta có :
$\frac{2}{5}$ .x + $\frac{1}{3}$ = $\frac{1}{5}$
=> $\frac{2}{5}$ .x = $\frac{1}{5}$ - $\frac{1}{3}$
=> $\frac{2}{5}$ .x = $\frac{-2}{15}$
=> x = $\frac{-2}{15}$ : $\frac{2}{5}$
=> x = $\frac{-1}{3}$
Vậy x = $\frac{-1}{3}$
b ) Ta có :
$\frac{4}{9}$ - $\frac{5}{3}$ . x = - 2
=> $\frac{5}{3}$ . x = - 2 - $\frac{4}{9}$
=> $\frac{5}{3}$ . x = $\frac{-22}{9}$
=> x = $\frac{-22}{9}$ : $\frac{5}{3}$
=> x = $\frac{-22}{15}$
Vậy x = $\frac{-22}{15}$
c ) Ta có :
$\frac{1}{5}$ + $\frac{5}{3}$ : x = $\frac{1}{2}$
=> $\frac{5}{3}$ : x = $\frac{1}{2}$ - $\frac{1}{5}$
=> $\frac{5}{3}$ : x = $\frac{3}{10}$
=> x = $\frac{5}{3}$ : $\frac{3}{10}$
=> x = $\frac{50}{9}$
Vậy x = $\frac{50}{9}$
d ) Ta có :
$\frac{5}{7}$ : x - 3 = $\frac{-2}{7}$
=> $\frac{5}{7}$ : x = 3 + $\frac{-2}{7}$
=> $\frac{5}{7}$ : x = $\frac{19}{7}$
=> x = $\frac{5}{7}$ : $\frac{19}{7}$
=> x = $\frac{5}{19}$
Vậy x = $\frac{5}{19}$
