40 × x = 1400;

x = 1400 : 40

x = 35

a) 40 × x = 1400;

x = 1400 : 40

x = 35

a)40 x 35 =1400

b) 2665 : 13 = 205

a/ x= 1400:40

   x=35

b/x=205.13

x=2665

a) 40 nhân x = 1400

x=1400:40

x=35

b)x:13=205

x=205x13

x=2665

chúc bn học tốt

a) 40 x X = 1400

           X = 1400:40

           X = 35

b) x : 13 = 205

          x = 205 x 13

          x = 2665

a, 40 x \(x\) = 1400

       \(x\) = 1400 : 40

       \(x\) = 35

b, \(x\) : 13 = 205

           \(x\) = 205 x 13

           \(x\) = 2665

a, 40 x X = 1400

X = 1400 : 40

X = 35

b, X : 13 = 205

X = 205 x 13

X = 2665

qua de! em hoc lop 5 ; em cung lam duoc cj tran thi thuy ten a!

ở đây là S đâu pải M đâuNguyễn Phúc

Đầu tiên rút gọn M trước 
M= 5/28 + 5/70 +.....+10/700 
= 5/(4.7)+5/(7.10)+....5/(25.28) 
3M= 5( 1/4 - 1/7 +1/7-1/10+......+1/25-1/28) 
3M= 5 (1/4-1/28) 
3M=15/14 
M= 5/14 :D 

\(S=\frac{10}{56}+\frac{10}{140}+\frac{10}{260}+.......+\frac{10}{1400}\)

\(S=\frac{5}{28}+\frac{5}{70}+\frac{5}{130}+\frac{5}{700}\)

\(\frac{3S}{5}=\frac{3}{4}\times7+\frac{3}{7}\times10+\frac{30}{10}\times13+........+\frac{3}{25}\times28\)

\(\frac{3S}{5}=\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+\frac{1}{10}-\frac{1}{13}+......+\frac{1}{25}-\frac{1}{28}\)

\(\frac{3S}{5}=\frac{1}{4}-\frac{1}{28}\)

\(\frac{3S}{5}=\frac{3}{14}\)

\(S=\frac{3}{14}\times\frac{5}{3}\)

\(S=\frac{5}{14}\)

Vậy \(S=\frac{5}{14}\)

\(9576:x=1400-1372\)
\(\Rightarrow9576:x=28\)
\(\Rightarrow x=9576:28\)
\(\Rightarrow x=342\)

9576 : x = 28

           x= 9576 : 28

           x= 342

\(\text{9576:X=1400-1372}\)

\(\text{9576:X=28}\)

        \(\text{X=}9576:28\)

        \(\text{X=}342\)

\(Suyra:\text{X=}342\)

x=56/1400=1/25

x=56:1000

x=0,056

1/25