Tìm x, biết: a) 3,14 - x = 8,34. b) 1 3/4- 2.(1/2 + x)=3/2

a) \[3,14 - x = 8,34\]

    \[x = 3,14 - 8,34\]

    \[x =  - 5,2\]

Vậy \[x =  - 5,2\].

b) \(1\frac{3}{4} - 2.\left( {\frac{1}{2} + x} \right) = \frac{3}{2}\)

\(2\left( {\frac{1}{2} + x} \right) = \frac{7}{4} - \frac{3}{2}\)

\(2\left( {\frac{1}{2} + x} \right) = \frac{1}{4}\)

\(\frac{1}{2} + x = \frac{1}{8}\)

\(x = \frac{1}{8} - \frac{1}{2}\)

\(x = \frac{{ - 3}}{8}\)

Vậy \(x = \frac{{ - 3}}{8}\).