Question

a)1,5+5/4.x=2/3

b)(2,7.x - 3/2.x ):2/7 =-21/4

Tính hợp lý 

12/19.7/15.-13/17.19/12.17/13

Answer 1

Tìm x

a,\(\frac{5}{4}x=\frac{2}{3}-1,5=\frac{2}{3}-\frac{3}{2}=\frac{4}{6}-\frac{9}{6}=\frac{-5}{6}\)

\(x=\frac{-5}{6}:\frac{5}{4}=\frac{-5}{6}.\frac{4}{5}=\frac{5.\left(-1\right).2.2}{2.3.5}=\frac{-2}{3}\)

Answer 2

b, \(\frac{2}{7}x-\frac{3}{2}x=\frac{-21}{4}.\frac{2}{7}=\frac{-3}{2}\)

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

\(x.\frac{-17}{14}=\frac{-3}{2}\)

\(x=\frac{-3}{2}:\frac{-17}{14}=\frac{-3}{2}.\frac{14}{-17}=\frac{21}{17}\)