2x + 11 = 3.(-9)

2x = -27-11

2x = -38

X = -38:2

X= -19

Vậy x = -19

a,\(x^4:9=9\\ \Leftrightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)

b,\(x^2-30=6\\ \Leftrightarrow x^2=36\Leftrightarrow\orbr{\begin{cases}x=6\\x=-6\end{cases}}\)

c,\(x^2:10=10\Leftrightarrow x^2=\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)

x⁴ : 9 = 9

x⁴ = 9 . 9

x⁴ = 81

x⁴ = 3⁴

=> x = 3

x² - 30 = 6

x² = 6 + 30

x² = 36

x² = 6²

=> x = 6

x² : 10 = 10

x² = 10 . 10

x² = 100

x² = 10²

=> x = 10

1. ta có: \(\sqrt{\dfrac{4}{9}-\sqrt{\dfrac{25}{36}}}=\sqrt{\dfrac{4}{9}-\dfrac{5}{6}}=\sqrt{-\dfrac{7}{18}}\)

Mà \(-\dfrac{7}{18}\) là số âm \(\Rightarrow\) Bài toán không có kết quả.

2. Ta có:

\(\left(x-1\right)^2=\dfrac{9}{16}\)

\(\Rightarrow\left(x-1\right)^2=\left(\dfrac{3}{4}\right)^2\)

\(\Rightarrow x-1=\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{3}{4}+1\)

\(\Rightarrow x=1\dfrac{3}{4}\)

Vậy \(x=1\dfrac{3}{4}\)

Câu 2 không phải toán lớp 6 mà bạn.

Ta có: \(x=\sqrt{x}\)

\(\Rightarrow x=1\)

Vậy \(x=1\)

Bạn Trần Đăng Nhất làm thiếu nha:

\(x=\sqrt{x}=>x^2=\left(\sqrt{x}\right)^2\)

\(=>x^2=x=>x^2-x=0\)

\(=>x\left(x-1\right)=0\)

\(=>\left[{}\begin{matrix}x=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

Vậy có 2 giá trị của x là 0 và 1..

CHÚC BẠN HỌC TỐT.....

\(x\div\left(9\dfrac{1}{2}-\dfrac{3}{2}\right)=\dfrac{0,4+\dfrac{2}{9}-\dfrac{2}{11}}{1,6+\dfrac{8}{9}-\dfrac{8}{11}}\)

\(x\div\left(\dfrac{19}{2}-\dfrac{3}{2}\right)=\dfrac{\dfrac{28}{45}-\dfrac{2}{11}}{\dfrac{112}{45}-\dfrac{8}{11}}\)

\(x\div8=\dfrac{\dfrac{218}{495}}{\dfrac{872}{495}}\)

\(\Rightarrow x\div8=\dfrac{218}{495}\div\dfrac{872}{495}\)

\(x\div8=\dfrac{1}{4}\)

\(x=\dfrac{1}{4}\times8\)

\(x=2\)

Vậy \(x=2\)

còn kết luận nha 

sai bạn ạ

a. \(\frac{x+1}{2}=\frac{8}{x+1}\)

\(\Leftrightarrow\left(x+1\right).\left(x+1\right)=8.2\)

\(\Leftrightarrow\left(x+1\right)^2=16\)

\(\Leftrightarrow\left(x+1\right)^2=2^4\)

\(\Leftrightarrow\left(x+1\right)=2^2\)

\(\Leftrightarrow\left(x+1\right)=4\)

\(\Leftrightarrow x=4-1=3\)

b. \(x:\left(9\frac{1}{2}-\frac{3}{2}\right)=\frac{0,4+\frac{2}{9}-\frac{2}{11}}{1,6+\frac{8}{9}-\frac{8}{11}}\)

\(\Leftrightarrow x:\left(\frac{10}{2}-\frac{3}{2}\right)=\frac{0,4+0,2-0,18}{1,6+0,8-0,72}\)

\(\Leftrightarrow x:\frac{7}{2}=\frac{\frac{21}{50}}{\frac{42}{25}}\)

\(\Leftrightarrow x=\frac{\frac{21}{50}}{\frac{42}{25}}.\frac{7}{2}\Leftrightarrow x=\frac{1}{4}.\frac{7}{2}=\frac{7}{8}\)

a )  \(\frac{x+1}{2}=\frac{8}{x+1}\)

\(\Rightarrow\left(x+1\right).\left(x+1\right)=2.8\)

\(\Rightarrow\left(x+1\right)^2=16\)

\(\Rightarrow\orbr{\begin{cases}x+1=4\\x+1=-4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=4-1\\x=-4-1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=3\\x=-5\end{cases}}\)

Dấu " \(\orbr{\begin{cases}\\\end{cases}}\)là hoặc nha !!! 

a, \(2\frac{7}{9}-\frac{12}{13}x=\frac{7}{9}\)

\(\Leftrightarrow\frac{25}{9}-\frac{12}{13}x=\frac{7}{9}\Leftrightarrow\frac{12}{13}x=2\Leftrightarrow x=\frac{13}{6}\)

b, \(\frac{x-12}{4}=\frac{9-3x}{x}\)

\(\Leftrightarrow x^2-12x=36-12x\Leftrightarrow x^2-12x-36+12x=0\)

\(\Leftrightarrow x^2-36=0\Leftrightarrow x^2=36\Leftrightarrow x=\pm6\)

Tự làm

giúp mk vs

lm đc câu nào thì lm 

mk k