Tìm x biết:
a) \(1\frac{5}{6} + x = \frac{7}{3}\)
b) \(x - \frac{3}{{ - 2}} = 3\frac{4}{5}\)
c) \(x:\frac{3}{{ - 5}} = 3\frac{1}{2}\)
d) \(2\frac{1}{6}.x = \frac{{ - 2}}{5}\)
Chuyển x sang một vế, đổi các hỗn số thành phân số, bài toán đưa về cộng, trừ, nhân, chia hai phân số.
a)
\(\begin{array}{l}1\frac{5}{6} + x = \frac{7}{3}\\x = \frac{7}{3} - 1\frac{5}{6}\\x = \frac{7}{3} - \frac{{11}}{6}\\x = \frac{{14}}{6} - \frac{{11}}{6}\\x = \frac{3}{6} = \frac{1}{2}\end{array}\)
b)
\(\begin{array}{l}x = 3\frac{4}{5} + \frac{3}{{ - 2}}\\x = \frac{{19}}{5} + \frac{3}{{ - 2}}\\x = \frac{{38}}{{10}} + \frac{{ - 15}}{{10}}\\x = \frac{{23}}{{10}}\end{array}\)
c)
\(\begin{array}{l}x:\frac{3}{{ - 5}} = 3\frac{1}{2}\\x = 3\frac{1}{2}.\frac{3}{{ - 5}}\\x = \frac{7}{2}.\frac{3}{{ - 5}}\\x = \frac{{ - 21}}{{10}}\end{array}\)
d)
\(\begin{array}{l}2\frac{1}{6}.x = \frac{{ - 2}}{5}\\x = \frac{{ - 2}}{5}:2\frac{1}{6}\\x = \frac{{ - 2}}{5}:\frac{{13}}{6}\\x = \frac{{ - 2}}{5}.\frac{6}{{13}}\\x = \frac{{ - 12}}{{65}}\end{array}\)