\(7.14+7.14+7.14\cdot8\)

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

\(=7.14\cdot10\)

\(=71.4\)

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

a)  = 9,42kg *3 =  28,26 kg

b) = 8,5m2 *( 1+1+4) = 8,5 m2 * 6 = 51 m2

c)  = 6,3 ha*(1+9)  =  6,3 ha * 10 = 63 ha

a ) 9,42kg x 3 = 28,26 kg

b ) 8,5 m² x 3 = 25,5 m

a) 9,42kg + 9,42kg + 9,42kg = 9,42kg x 3                       b) 8,5 m2 + 8,5 m2 + 8,5 m2 x 4 = 8,5 m2 x ( 3 +4 )

                                              = 28,26 kg                                                                               = 8,5 m2 x 7

                                                                                                                                              = 59,5 m2

c) 6,3 ha + 6,3 ha x 9 = 6,3 ha x ( 2 + 9 )

                                  = 6,3 ha x 11

                                  = 69,3 ha.

Mik chẳng bik có đúng ko nữa ! Học tốt !

6.75*3=20.25

(7.14*3)*3=64.26

(9.26*2)*9=166.68

5.8*3*3=52,2

ban oi hinh nhu ban lam sai roi

  7 x 14m² +7 x 14m² + 7 x 14m²

= (7+7+7) x ( 14m²+ 14m²+ 14m²)

=7 x 3 + 14m²x 3

=21 + 42m²

\(\frac{2}{3}-\frac{5}{7}\cdot\frac{14}{225}\)

\(=\frac{2}{3}-\frac{2}{45}\)

\(=\frac{28}{45}\)

Tk mk nha!

 \(\frac{2}{3}-\frac{5}{7}\cdot\frac{14}{225}\)

\(=\frac{2}{3}-\frac{5\cdot14}{7\cdot225}\)

\(=\frac{2}{3}-\frac{5\cdot7\cdot2}{7\cdot5\cdot45}\)

\(=\frac{2}{3}-\frac{2}{45}\)

\(=\frac{30}{45}-\frac{2}{45}\)

\(=\frac{28}{45}\)

tk mình nha!   ◘_◘

2/3-5/7.14/225=2/3-2/45=28/45

NHA 

sorry

ai gúp tớ với

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

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

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

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

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

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

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

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

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

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