38/24 : (-3) =???
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1/
$M=\frac{1}{3.8}+\frac{1}{8.13}+\frac{1}{13.18}+....+\frac{1}{33.38}$
$5M=\frac{8-3}{3.8}+\frac{13-8}{8.13}+\frac{18-13}{13.18}+...+\frac{38-33}{33.38}$
$=\frac{1}{3}-\frac{1}{8}+\frac{1}{8}-\frac{1}{13}+\frac{1}{13}-\frac{1}{18}+....+\frac{1}{33}-\frac{1}{38}$
$=\frac{1}{3}-\frac{1}{38}=\frac{35}{114}$
$\Rightarrow M=\frac{35}{114}:5=\frac{7}{114}$
2/
$N=\frac{1}{3.10}+\frac{1}{10.17}+\frac{1}{17.24}+\frac{1}{24.31}+\frac{1}{31.38}$
$7N=\frac{10-3}{3.10}+\frac{17-10}{10.17}+\frac{24-17}{17.24}+\frac{31-24}{24.31}+\frac{38-31}{31.38}$
$=\frac{1}{3}-\frac{1}{10}+\frac{1}{10}-\frac{1}{17}+\frac{1}{17}-\frac{1}{24}+\frac{1}{24}-\frac{1}{31}+\frac{1}{31}-\frac{1}{38}$
$=\frac{1}{3}-\frac{1}{38}=\frac{35}{114}$
$\Rightarrow N=\frac{35}{114}:7=\frac{5}{114}$
a)
= (125 + 875)*3
= 1000*3
= 3000
b)
= (38 +62)*24
= 100*4
= 400
~~Học tốt nha~~
a. phai la 125x3+875x3 moi dung nhe!
= 3( 125+875)
= 3x 1000
= 3000
b. 38x24+62x24
=24(38+62)
= 24x 100
= 2400
Chuc e hoc gioi nhe!!!
107 - {38 - [7 x 32 - 24 : 6 + (9 - 7)3]} : 15
= 107 - {38 - [7 x 9 - 4 + 23]} : 15
= 107 - {38 - [63 - 4 + 8]} : 15
= 107 - {38 - [59 + 8]} : 15
= 107 - (38 - 67) : 15
= 107 - (-29) : 15
= 107 - (-1,99)
= 107 + 1,99
= 108,99
107-{38+[7.3^2-24:6+(9-7)^3]}:15
=107-{38+[7.9-24:6+23]} :15
=107-{38+[63-4+8]}:15
=107-{38+67}:15
=107-105:15
=107-7=7
Lời giải:
$\frac{24}{19}+\frac{7}{38}+\frac{31}{38}+\frac{5}{38}$
$=\frac{48}{38}+\frac{7}{38}+\frac{31}{38}+\frac{5}{38}$
$=\frac{48+7+31+5}{38}=\frac{91}{38}$
Gọi 3 phần đó là a,b,c(24>b>c>a>0)
Áp dụng tc dtsbn:
\(\dfrac{a}{32}=\dfrac{b}{38}=\dfrac{c}{36}=\dfrac{a+b+c}{32+38+36}=\dfrac{24}{106}=\dfrac{12}{53}\\ \Leftrightarrow\left\{{}\begin{matrix}a=\dfrac{384}{53}\\b=\dfrac{456}{53}\\c=\dfrac{432}{53}\end{matrix}\right.\)
= -19/36
\(\dfrac{38}{24}:\left(-3\right)=-\dfrac{19}{36}\)