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\(4\&\frac{2}{5}.0,5-1\&\frac{3}{7}.14\%+\left(-0,8\right)\)

\(\frac{2}{5}.0,5-1=\frac{2}{5}.\frac{5}{10}-1=\frac{1}{5}-\frac{5}{5}=\frac{-4}{5}\)

\(\frac{3}{7}.14\%+\left(-0.8\right)=\frac{3}{7}.\frac{7}{50}-\frac{4}{5}=\frac{3}{50}-\frac{40}{50}=\frac{-37}{50}\)

\(VI\frac{-4}{5}=\frac{-40}{50}< \frac{-37}{50}MA\frac{-37}{50}< 0< 4\Rightarrow\frac{-4}{5}< \frac{-37}{50}< 4\)⁽¹⁾

^{TỪ 1 =>\(\frac{2}{5}.0,5-1< \frac{3}{7}.14\%+\left(-0,8\right)< 4\)}

7,14x5=35,7

tk nha

7,14+7,14+7,14x3

=7,14x(1+1+3)

=7,14x5

=35,7

\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)

\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)

\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)

a: \(=\dfrac{16-25}{20}=\dfrac{-9}{20}\)

b: \(=\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}=-\dfrac{23}{30}\)

c: \(=\dfrac{2}{3}-\dfrac{1}{5}\cdot2=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)

d: \(=\dfrac{12-25}{30}\cdot\dfrac{15}{8}-1=\dfrac{-13}{16}-1=\dfrac{-29}{16}\)

e: \(=\dfrac{-3}{13}-\dfrac{10}{13}-\dfrac{7}{17}+\dfrac{24}{17}-\dfrac{5}{19}-\dfrac{14}{19}=-1\)

6.75*3=20.25

(7.14*3)*3=64.26

(9.26*2)*9=166.68

`#` `\text{dkhanhqlv}`

`4)`

`a)3.(-5/11)`

`=-15/11`

`b)3/5+4/7 . 14/6`

`=3/5 + 4/3`

`=9/15+20/15`

`=29/15`

`c) 10/21-3/8 . 4/15`

`=10/21-1/10`

`=100/210-21/210`

`=79/100`

`d)(2/3+3/4)(5/7+5/14)`

`=(8/12+9/12)(10/14+5/14)`

`=17/12 . 15/14`

`=85/56`

`5)`

`a)x-1/2=3/10 . 5/6`

`=>x-1/2=1/4`

`=>x=1/4+1/2`

`=>x=1/4+2/4`

`=>x=3/4`

`b)x/5 = -3/14`

`=>x : 5 = -3/14`

`=>x=-3/14 . 5`

`=>x=-15/14`

`c)x+2/3=9/15 . 5/27`

`=>x+2/3=1/9`

`=>x=1/9-2/3`

`=>x=1/9-6/9`

`=>x=-5/9`

\(7.14+7.14+7.14\cdot8\)

\(=7.14\cdot\left(1+1+8\right)\)

\(=7.14\cdot10\)

\(=71.4\)

k hộ mk nhé!!!!

~ học tốt ~

\(7,14+7,14+7,14\)x \(8\)

\(=7,14X3X8\)

\(=21,42X8=171,36\)

 7.14+7.14+7.14*8

=7,14*(1+1+8)

=7,14*10

=71,4

  7 x 14m² +7 x 14m² + 7 x 14m²

= (7+7+7) x ( 14m²+ 14m²+ 14m²)

=7 x 3 + 14m²x 3

=21 + 42m²

\(\frac{5}{7}.\frac{5}{11}+\frac{5}{7}.\frac{2}{11}-\frac{5}{7}.\frac{14}{11}\)

\(=\frac{5}{7}.\left(\frac{5}{11}+\frac{2}{11}-\frac{14}{11}\right)\)

\(=\frac{5}{7}.\frac{-7}{11}\)

\(=\frac{-5}{11}\)

5/7.5/11+5/7.2/11-5/7.14/11

= 5/7.(5/11+2/11-14/11)

=5/7.-7/11

=-5/11

5/7 + 5/11 + 5/7 . 2/11 - 5/7 .14/11

=5/7.(5/11+2/11-14/11)

=5/7.(5+2-4/11)

=5/7.(-7/11)

=-5/11