Đáp án:
a/$x=\frac{-21}{2}$
b/$x=\frac{13}{45}$
c/$x = \frac{7}{24}$
Giải thích các bước giải:
a/$\frac{1}{7}.x=\frac{-3}{2}$
$x=\frac{-3}{2} : \frac{1}{7}$
$x=\frac{-21}{2}$
.
b/$\frac{2}{15}-x=\frac{-7}{45}$
$x=\frac{2}{15}-\frac{-7}{45}$
$x=\frac{13}{45}$
.
c/$2 . (\frac{3}{24} - x )+ \frac{3}{4}= \frac{5}{12}$
$2 . (\frac{3}{24} - x )= \frac{5}{12}- \frac{3}{4}$
$2 . (\frac{3}{24} - x ) = \frac{-1}{3}$
$\frac{3}{24} - x = \frac{-1}{3} :2$
$\frac{3}{24} - x = \frac{-1}{6}$
$x = \frac{3}{24} - \frac{-1}{6}$
$x = \frac{7}{24}$
$#minhthong2009$
