\(5\left(x-3\right)=25\)

\(x-3=25:5=5\)

\(x=5+3=8\)

\(x-3=5=5x=8\)

Hình như sai đề

\(10+2x=16\)

\(2x=6\)

\(x=3\)

mik còn k pit bn hỏi cái dj

trong sách bt

a)\(8\sqrt{x}-3\sqrt{\frac{4}{81}}=5,2\)

\(\Rightarrow8\sqrt{x}-3.\frac{2}{9}=5,2\)

\(\Rightarrow8\sqrt{x}-\frac{2}{3}=5,2\)

\(\Rightarrow8\sqrt{x}=5,2+\frac{2}{3}\)

\(\Rightarrow8\sqrt{x}=\frac{40}{3}\)

\(\Rightarrow\sqrt{x}=\frac{40}{3}:8\)

\(\Rightarrow\sqrt{x}=\frac{5}{3}\)

\(\Rightarrow x=\frac{25}{9}\)

b)\(12-3x^2=10+\sqrt{\frac{25}{16}}\)

\(\Rightarrow12-3x^2=10+\frac{5}{4}\)

\(\Rightarrow12-3x^2=11,25\)

\(\Rightarrow3x^2=12-11,25\)

\(\Rightarrow3x^2=0,75\)

\(\Rightarrow x^2=0,25\)

\(\Rightarrow x=\sqrt{0,25}\)

\(\Rightarrow x=0,5\)

b,\(12-3x^2=10+\sqrt{\dfrac{25}{16}}\)

\(\Leftrightarrow12-3x^2=\dfrac{45}{4}\)

\(\Leftrightarrow3x^2=\dfrac{3}{4}\)

\(\Leftrightarrow x^2=\dfrac{1}{4}\)

\(\Leftrightarrow x=\sqrt{\dfrac{1}{4}}=\dfrac{1}{2}\)

Vậy...

Tìm x 

25-x=12,8

x=25-12,8

x=12,2

25-x=12,8

=>x=25-12,8

=>x=12,2

 Vậy x=12,2

\(=>x=25-12,8=12,2\)

a: \(x\in\varnothing\)

\(\dfrac{7011}{25}:\left(x-42.6\right).15=13\)

\(\Rightarrow\dfrac{7011}{\dfrac{25}{\left(x-42,6\right)}}.0,15=13\)

\(\Rightarrow\dfrac{280,44}{\left(x-42,6\right)}.0,15=13\)

\(x-\left(280,44-42,6\right)\)

\(x=237.8+86,7\)

\(x=324,54\)

\(\)Vậy x=324,54

b.

\(7,2-\left(x+3,75:2,1\right):1,9=5,2\)

\(\Rightarrow7,2+\dfrac{-\left(x-\dfrac{3,75}{2,1}\right)}{1,9}=5,2\)

\(7,2+\dfrac{-\left(x-1,8\right)}{1,9}=5,2\)

25 : x = 16 : 10

25 : x = 1,6

x = 25 : 1,6

x = 15,625

25 : x = 16 : 10

25 : x = 1,6

x = 25 : 1,6

x = 15,625