Question

tìm x thuộc z biết

\(\frac{-3}{4}<\frac{x}{12}<\frac{-1}{3}\)

Answer 1

-3/4<x/12<-1/3

=quy đồng mẫu ta được

-9/12<12//12<-4/12

.............

Answer 2

ta co:-3 phan 4 = -9 phan 12 ; -1 phan 3 = -4 phan 12

-3 phan 4 < x phan 12 < -1 phan 3

nen;-9 phan 12 < x phan12 < -4 phan 12

suy ra : x thuoc {-8 ; -7; -6; -5}

Answer 3

=\(\frac{5}{10}-\frac{5}{11}+\frac{5}{11}-\frac{5}{12}+\frac{5}{12}-\frac{5}{13}+\frac{5}{13}-\frac{5}{14}+\frac{5}{14}-\frac{5}{15}\)

=\(\frac{5}{10}-\frac{5}{15}\)

=\(\frac{1}{2}-\frac{1}{3}\)

=\(\frac{1}{6}\)