`a) 1/2 + 1/4 + 1/5`
`=10/20 + 5/20 + 4/20`
`= 19/20`

`b)1/2xx 4/5 : 1/4`
`= 4/10 : 1/4`
`= 8/5`

\(a\)/ \(\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{5}=\dfrac{11}{20}\)

\(b\)/ \(\dfrac{1}{2}.\dfrac{4}{5}:\dfrac{1}{4}=\dfrac{8}{5}\)

ko ai trả lời à ? Định mệnh

89/34

89/34 nhớ k cho mình nha!

a)    \(\frac{1}{2}+\frac{1}{4}-\frac{1}{5}=\frac{10}{20}+\frac{5}{20}-\frac{4}{20}=\frac{10+5-4}{20}=\frac{11}{20}=0,55\)

b)    \(\frac{1}{2}.\frac{2}{5}:\frac{1}{4}=\frac{1}{2}.\frac{2}{5}.4=\frac{1.2.4}{2.5}=0,8\)

1/2+1/4-1/5=11/20

1/2*2/5:1/4=4/5

a)1/2+1/4-1/5=11/20

b)1/2X2/5:1/4=4/5

CHÚC BẠN HỌC TỐT !

a)  3 : 4  =  = 0,75.

b) 7 : 5 =  = 1,4 .

c) 1 : 2  =  = 0,5

d) 7 : 4 =  = 1,75.

 a)  3 : 4  =  = 0,75.

b) 7 : 5 =  = 1,4 .

c) 1 : 2  =  = 0,5

d) 7 : 4 =  = 1,75.

a, \(\dfrac{3}{4}=0,75\)

b, \(\dfrac{7}{5}=1,4\)

c, \(\dfrac{1}{2}=0,5\)

d, \(\dfrac{7}{4}=1,75\)

a)2 phần 5

b)4 phần 5

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

\(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}=\frac{1}{2}\times\frac{4}{3}\times\frac{6}{5}=\frac{1\times2\times2}{5}=\frac{4}{5}\)

\(\frac{2}{3}.\frac{3}{4}.\frac{4}{5}=\frac{2}{5}=\frac{4}{10}=0,4\)

\(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}=\frac{1}{2}.\frac{4}{3}.\frac{6}{5}=\frac{4}{5}=\frac{8}{10}=0,8\)

=1/21 nha bạn

= 1/21 đó bn...tích dùm mk nha!!

a. x=-11,5

b. x=-0,375