\(\frac{5}{2}\)x\(\frac{1}{3}\)+\(\frac{1}{4}\)= \(\frac{5}{6}\)+\(\frac{1}{4}\)= \(\frac{10}{12}\)+\(\frac{3}{12}\)= \(\frac{13}{12}\)

\(\frac{5}{2}\)-\(\frac{1}{3}\):\(\frac{1}{4}\)= \(\frac{5}{2}\)-\(\frac{1}{3}\)x\(\frac{4}{1}\)= \(\frac{5}{2}\)-\(\frac{4}{3}\)= \(\frac{15}{6}\)-\(\frac{8}{6}\)=\(\frac{7}{6}\)

Chi tiết lun nha, nhớ k đúng cho mik nha :33

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

\(=\frac{5}{6}+\frac{1}{4}\)

\(=\frac{10}{12}+\frac{3}{12}\)

\(=\frac{13}{12}\)

\(\frac{5}{2}-\frac{1}{3}\div\frac{1}{4}\)

\(=\frac{5}{2}-\frac{1}{3}\times\frac{4}{1}\)

\(=\frac{5}{2}-\frac{4}{3}\)

\(=\frac{15}{6}-\frac{8}{6}\)

\(=\frac{7}{6}\)

=2.x= -5.(-4)

= -5 . (-4) trên 2

=Vậy x= 10

-3/21+-2/7

thực hiện phép tính         

  -3/21+-2/7

a )  \(-\frac{3}{7}.\frac{3}{11}+-\frac{3}{7}.\frac{8}{11}+1\frac{3}{7}\)

\(=-\frac{3}{7}.\left(\frac{3}{11}+\frac{8}{11}\right)+\frac{10}{7}\)

\(=-\frac{3}{7}.\frac{11}{11}+\frac{10}{7}\)

\(=-\frac{3}{7}.1+\frac{10}{7}\)

\(=\frac{10}{7}\)

b )   \(75\%.10,5=\frac{3}{4}.10,5=7,875\)

c )  \(5-3.\left(\left|-4\right|-30:15\right)\)

\(=5-3.\left(4-2\right)\)

\(=5-3.2\)

\(=5-6\)

\(=-1\)

d )  \(-\frac{5}{7}.\frac{2}{11}+-\frac{5}{7}.\frac{9}{11}+1\frac{5}{7}\)

\(=-\frac{5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{12}{7}\)

\(=-\frac{5}{7}.1+\frac{12}{7}\)

\(=\frac{7}{7}\)

\(=1\)

Chúc bạn học tốt !!!