Đáp án: c ) x = $\frac{-43}{49}$
e ) x = $\frac{-7}{12}$
Giải thích các bước giải:
c ) 1$\frac{2}{5}$ * x + $\frac{3}{7}$ = $\frac{-4}{5}$
$\frac{7}{5}$ * x = $\frac{-4}{5}$ - $\frac{3}{7}$
$\frac{7}{5}$ * x = $\frac{-43}{35}$
x = $\frac{-43}{35}$ : $\frac{7}{5}$
x = $\frac{-43}{49}$
e ) $\frac{-1}{2}$ + 2x =- 1$\frac{2}{3}$
$\frac{-1}{2}$ + 2x = $\frac{-5}{3}$
2x = $\frac{-5}{3}$ - $\frac{-1}{2}$
2x = $\frac{-7}{6}$
x = $\frac{-7}{6}$ : 2
x = $\frac{-7}{12}$
