\(\dfrac{4\times x}{1\times5}\) + \(\dfrac{4\times x}{5\times9}\) + \(\dfrac{4\times x}{9\times13}\) + \(\dfrac{4\times x}{13\times17}\) = 16

\(x\times\left(\dfrac{4}{1\times5}+\dfrac{4}{5\times9}+\dfrac{4}{9\times13}+\dfrac{4}{13\times17}\right)\) = 16

\(x\) \(\times\) (\(\dfrac{1}{1}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{1}{9}\) + \(\dfrac{1}{9}\) - \(\dfrac{1}{13}\) + \(\dfrac{1}{13}\) - \(\dfrac{1}{17}\)) = 16

\(x\) \(\times\) ( \(\dfrac{1}{1}\) - \(\dfrac{1}{17}\)) = 16

\(x\) \(\times\) \(\dfrac{16}{17}\)  = 16

\(x\)            = 16 : \(\dfrac{16}{17}\)

\(x\)             = 17 

`4 xx x -x-x=1,07`

`=> 4 xx x - x xx 1 - x xx 1=1,07`

`=> (4-1-1) xx x=1,07`

`=> 2 xx x =1,07`

`=> x=1,07 : 2`

`=>x=0,535` 

`4xx x-x-x=107`

`=>x xx (4-1-1)=1,07`

`=> x xx 2=1,07`

`=>x=1,07:2`

`=>x=0,535`

a) => x : 80 = 2

=> x = 160

b) => 200/15 : x = 3

=> x = 40/9

c) => 158 - x = 140

=> x = 18

d) => 231 - (x-6) = 103

=> x - 6 = 128

=> x = 134

\(\frac{3}{8}\times x+\frac{1}{4}\times x=\frac{2}{5}\)

\(\Rightarrow x\times\left(\frac{3}{8}+\frac{1}{4}\right)=\frac{2}{5}\)

\(\Rightarrow x\times\frac{5}{8}=\frac{2}{5}\)

\(\Rightarrow x=\frac{16}{25}\)

~Std well~

#Thạc_Trân

bn ơi / là j bn

\(\frac{3}{8}\times x+\frac{1}{4}\times x=\frac{2}{5}\)

\(\left(\frac{3}{8}+\frac{1}{4}\right)\times x=\frac{2}{5}\)

\(\frac{5}{8}\times x=\frac{2}{5}\)

Đến đây tự làm :v

\(75\%x+\frac{3}{4}x+x=30\)

\(\Leftrightarrow\left(75\%+\frac{3}{4}+1\right)x=30\)

\(\Leftrightarrow\frac{5}{2}x=30\)

\(\Leftrightarrow x=30:\frac{5}{2}\)

\(\Leftrightarrow x=12\)

11x(x-6)=4xX+11

=>11x-66=4x+11

=>11x-4x=66+11

=>7x=77=>x=11

Toán khó vậy Việt !!!

4X + 3X + 2X + 1X = 100

\(\Rightarrow10x=100\\x=10\)

\(4x+3x+2x+x=100\)

\(\Leftrightarrow10x=100\Leftrightarrow x=\frac{100}{10}=10\)

Vậy \(x=10\)

( 4 x X - 0.8 ) : X + 14.5 = 16

( 4 x X - 0.8 ) : X = 16 - 14.5

4 x X - 0.8 = 1.5 x X

4 x X - 1.5 x X = 0.8

( 4 - 1.5 ) x X = 0.8

2.5 x X = 0.8

X = 0.8 : 2.5

X = 0.32

x= 0,32