x = 2,5

5,25 x 4,1 + (-2,05) x 16,4 + 2,625 x 8,2

= 21,525 + (-33,62) + 21,525

= (-12,095) +21,525 = 9,43

=4,1(5,25-2,05*4+2,625*2)

=4,1*2,3=9,43

a: \(2,5:4x=0,5:0,2\)

=>\(2,5:4x=0,5\cdot5=2,5\)

=>4x=1

=>\(x=\dfrac{1}{4}\)

b: \(3,8:2x=\dfrac{1}{4}:2\dfrac{2}{3}\)

=>\(3,8:2x=\dfrac{1}{4}:\dfrac{8}{3}=\dfrac{1}{4}\cdot\dfrac{3}{8}=\dfrac{3}{32}\)

=>\(2x=3,8:\dfrac{3}{32}=\dfrac{19}{5}\cdot\dfrac{32}{3}=\dfrac{608}{15}\)

=>\(x=\dfrac{608}{15}:2=\dfrac{304}{15}\)

c: \(5,25:7x=3,6:2,4\)

=>\(5,25:7x=1,5\)

=>\(7x=5,25:1,5=3,5\)

=>\(x=\dfrac{3.5}{7}=0,5\)

d: \(1,8:1,3=-2,7:5x\)

=>\(5x=-2,7:\dfrac{18}{13}=-2,7\cdot\dfrac{13}{18}=-1,95\)

=>\(x=-1,95:5=-0,39\)

7x.(2+x)-7x.(x+3)=14

7x.(2+x-x-3)=14

7x.(-1)=14

7x=14:(-1)

7x=-14

x=-14:7

x=2

Vậy x=2

tk nha!

Tìm x €Z biết

4.(2x+9)+(-8.x+3) -(x-13)=0

https://olm.vn/hoi-dap/tim-kiem?q=%7C2x-9%7C+%7C3x-13%7C-%7C14-5x%7C+%7C19-(4x+12)%7C=56t%C3%ACm+x&id=191953

\(\Leftrightarrow\left[{}\begin{matrix}14-19x=7x-15\\19x-14=7x-15\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}26x=29\\12x=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{29}{26}\\x=-\dfrac{1}{12}\end{matrix}\right.\)

x = 11                          

   ĐKXĐ: \(x\ne0\) 

\(\frac{7x}{10}=\frac{14}{x}\Rightarrow7x^2=140\Rightarrow x^2=20\Rightarrow\orbr{\begin{cases}x=2\sqrt{5}\\x=-2\sqrt{5}\end{cases}}\)

Vậy ............................... chúc bn hok tốt

\(\frac{7x}{5}+\frac{14}{x}\)

=>\(7x.x=5.14\)

=>\(7x^2=70\)

=>\(x^2=70:7=10\)

=>\(x=\sqrt{x}\)

7x/5=14/x

=>7x*x=14*5

7*x*x=70

x*x=70/7=10

x^2=10

7x + 14 = 42

7x         = 42 - 14

7x         = 28

  x         = 28 : 7

  x         = 4

Vậy x = 4

7x = 42 - 14 

7x = 28

x = 28 : 7

x = 4

7x=42-14

7x=28

x=28:7

x=4

a.

-2 (x+6)+6 (x-10)=8

-2x -12 +6x -60 =8

4x -72 =8

4x = -64

  x= -16

b.

7x (2+x) -7x (x+3) =14

7x [ (2+x)-(x+3) ] =14

7x (2+x-x-3) =14

-7x =14

x= -2