a) \(|x+7|+|2y-12|=0\)

Vì \(\hept{\begin{cases}|x+7|\ge0;\forall x,y\\|2y-12|\ge0;\forall x,y\end{cases}}\)\(\Rightarrow|x+7|+|2y-12|\ge0;\forall x,y\)

Do đó \(|x+7|+|2y-12|=0\)

\(\Leftrightarrow\hept{\begin{cases}|x+7|=0\\|2y-12|=0\end{cases}\Leftrightarrow}\hept{\begin{cases}x=-7\\y=6\end{cases}}\)

Vậy ...

các phần sau tương tự

a) Ta có :

\(\left|x+7\right|\ge0\)

\(\left|2y-12\right|\ge0\)

Để |x+7| + | 2y - 12| = 0

=> x +7 = 0      và      2y - 12= 0

     x  = 7                    2y = 12

                                    y = 12 : 2

                                   y = 6

Vậy x = 7 ; y = 6

Cái kia bị nhầm ạ :)

x + 7 = 0

x = -7 

a) chịu 

b) Ta có : |x| \(\ge0\forall x\in Z\)

               |y - 1| \(\ge0\forall x\in Z\)

Mà : |x| + |y - 1| = 0 

Nên : \(\hept{\begin{cases}\left|x\right|=0\\\left|y-1\right|=0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}x=0\\y-1=0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}x=0\\y=1\end{cases}}\)

Vậy x = 0 ; y = 1

a, \(12\left(x-1\right)=0\Rightarrow x-1=0\Rightarrow x=1\)

b, \(\left(x-47\right)-115=0\Rightarrow x-47-115=0\)

\(\Rightarrow x=115+47=162\)

c, \(x-36:18=12\Rightarrow x-2=12\Rightarrow x=14\)

d, \(\left(x-36\right):18=12\Rightarrow x-36=216\Rightarrow x=252\)

Chúc bạn học tốt!!!

\(a.12\left(x-1\right)=0\)

\(x-1=0:12\)

\(x-1=0\)

\(x=0+1\)

\(x=1\)

\(b.\left(x-47\right)-115=0\)

\(x-47=0+115\)

\(x-47=115\)

\(x=115+47\)

\(x=162\)

\(c.x-36:18=12\)

\(x-36=12.18\)

\(x-36=216\)

\(x=216+36\)

\(x=252\)

\(d.\left(x-36\right):18=12\)

\(x-36=12.18\)

\(x-36=216\)

\(x=216+36\)

\(x=252\)

a) 12 . ( x - 1 ) = 0

x - 1 = 0 : 12

x - 1 = 0

x = 0 + 1

x = 1

b) ( x - 47 ) - 115 = 0

x - 47 = 0 + 115

x - 47 = 115

x = 115 + 47

x = 162

c) x - 36 : 18 = 12

x - ( 36 : 18) = 12

x - 2 = 12

x = 12 + 2

x = 14

d) (x - 36) : 18 = 12

x - 36 = 12 . 18

x - 36 = 216

x = 216 + 36

x = 252

1) -12+3.(-x+7)=-18

   3.(-x+7)=-18+12

   3.(x+7)=-6

x+7=-6:3

x+7=-2

x=-2-7

x=-9

Trl :

   Bạn kia trả lời đúng rồi !

Hok tốt

~ nhé bạn ~

1)Ta có: \(12,\left(1\right)=12+0,\left(1\right)=12+\frac{1}{9}=\frac{109}{9}\);

\(2,3\left(6\right)=2,3+\frac{1}{10}\times0,\left(6\right)=2,3+\frac{1}{10}\times6\times0,\left(1\right)=2,3+\frac{1}{10}\times6\times\frac{1}{9}=\frac{71}{30}\)\(4,\left(21\right)=4+21\times0,\left(01\right)=4+21\times\frac{1}{99}=\frac{139}{33}\)

\(\Rightarrow\)\(\left[\frac{109}{9}-\frac{71}{30}\right]\div\frac{139}{33}=\frac{9647}{4170}\)

2)Ta có: \(0,\left(12\right)=12\times0,\left(01\right)=12\times\frac{1}{99}=\frac{4}{33}\)

\(1,\left(6\right)=1+6\times0,\left(1\right)=1+6\times\frac{1}{9}=\frac{5}{3}\)

\(0,\left(4\right)=4\times0,\left(1\right)=4\times\frac{1}{9}=\frac{4}{9}\)

\(\Rightarrow\frac{4}{33}\div\frac{5}{3}=x\div\frac{4}{9}\Rightarrow x\div\frac{4}{9}=\frac{4}{55}\Rightarrow x=\frac{4}{55}\times\frac{4}{9}\Rightarrow x=\frac{16}{495}\)

16/495

chuẩn rồi 16/495