Question

Tìm x biết:

a) ( x - 1/2) x 5/3 = 7/4 - 1/2

b) ( x - 4/3) x 7/4 = 5 - 7/6

Answer 1

\(\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{7}{4}-\frac{1}{2}\)

\(\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{7}{4}-\frac{2}{4}=\frac{5}{4}\)

\(x-\frac{1}{2}=\frac{5}{4}:\frac{5}{3}=\frac{5}{4}.\frac{3}{5}=\frac{3}{4}\)

\(x=\frac{3}{4}+\frac{1}{2}=\frac{3}{4}+\frac{2}{4}=\frac{5}{4}\)

Vậy \(x=\frac{5}{4}\)

b.\(\left(x-\frac{4}{3}\right).\frac{7}{4}=5-\frac{7}{6}\)

\(\left(x-\frac{4}{3}\right).\frac{7}{4}=\frac{23}{6}\)

\(x-\frac{4}{3}=\frac{23}{6}:\frac{7}{4}=\frac{23}{6}.\frac{4}{7}\)

\(x-\frac{4}{3}=\frac{46}{21}\)

\(x=\frac{46}{21}+\frac{4}{3}=\frac{46}{21}+\frac{28}{21}=\frac{74}{21}\)

Vậy \(x=\frac{74}{21}\)