M = 5/16 = 0,3125

k nha

M = 5/16 = 0,3125

Tích cho tớ để đạt 250 điểm nha xin đó

=0,3 125

M=20/8.14+20/14.20+20/20.26+20/26.32

=>M=20/6(6/8.14+6/14.20+6/20.26+6/26.32)

=>M=20/6(1/8-1/14+1/14-1/20+1/20-1/26+1/26-1/32)

=>M=20/6(1/8-1/32)

    = 20/6.3/32

    =5/16

Bằng 87.2

Bằng 87.2

\(M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}\)

\(M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}\)

\(M=\frac{20}{6}.\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)\)

\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)\)

\(M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{32}\right)\)

\(M=\frac{20}{6}\cdot\frac{3}{32}\)

\(M=\frac{5}{16}\)

$M=\frac{20}{112}+\frac{20}{280}+\frac{20}{520}+\frac{20}{832}$

$M=\frac{20}{8.14}+\frac{20}{14.20}+\frac{20}{20.26}+\frac{20}{26.32}$

$M=\frac{20}{6}.\left(\frac{6}{8.14}+\frac{6}{14.20}+\frac{6}{20.26}+\frac{6}{26.32}\right)$

$M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{14}+\frac{1}{14}-\frac{1}{20}+\frac{1}{20}-\frac{1}{26}+\frac{1}{26}-\frac{1}{32}\right)$

$M=\frac{20}{6}\left(\frac{1}{8}-\frac{1}{32}\right)$

$M=\frac{20}{6}\cdot \frac{3}{32}$

$M=\frac{5}{16}$

Dúng rồi 

mình kko biết

lớp 5 cũng làm đc

( 2x -280 +20 ) : 192 =0

<=>2x-280+20=0

<=>2x-280=-20

<=>2x=260

<=>x=130

( 2x - 280 + 20 ) : 192 = 0

=> 2x - 280 + 20 = 0

=> 2x - 280 = - 20

=> 2x = 260

=> x = 130

( 2x - 280 + 20 ) : 192 = 0

=> 2x - 280 + 20 = 0

=> 2x - 280 =  - 20

=> 2x = 260

=> x = 130