tham khảo

cái này đúng không nhỉ 

\(\Leftrightarrow4,5-2x=\dfrac{11}{14}:\dfrac{11}{7}\)

\(\Leftrightarrow4,5-2x=\dfrac{1}{2}\)

\(\Leftrightarrow2x=4,5-\dfrac{1}{2}\)

\(\Leftrightarrow x=4:2\)

\(\Leftrightarrow x=2\)

4,5 -2x = 11/14 : 1 4/7

4,5 -2x = 11/14 : 11/7

4,5 -2x =  1/2

2x = 4,5 - 1/2

2x = 4

x = 4 : 2

x = 2

d: =>-x-5/6=7/12-4/12=3/12=1/4

=>-x=1/4+5/6=13/12

hay x=-13/12

e: =>x+3=-5

hay x=-8

f: =>4,5-2x=-1/2

=>2x=5

hay x=5/2

=>4,5-2x=11/14:11/7=1/2

=>2x=4

hay x=2

\(\left(4,5-2x\right)\cdot1\dfrac{4}{7}=\dfrac{11}{14}\)

\(\left(\dfrac{9}{2}-2x\right)\cdot\dfrac{11}{7}=\dfrac{11}{14}\)

\(\dfrac{9}{2}-2x=\dfrac{11}{14}:\dfrac{11}{7}\)

\(\dfrac{9}{2}-2x=\dfrac{1}{2}\)

\(2x=\dfrac{9}{2}-\dfrac{1}{2}\)

\(2x=\dfrac{8}{2}\)

\(x=\dfrac{8}{2}:2\)

`x=2`

(4,5 - 2\(x\)) (-1\(\dfrac{4}{7}\)) = \(\dfrac{11}{14}\)

(4,5 - 2\(x\)) (-\(\dfrac{11}{7}\)) = \(\dfrac{11}{14}\)

4,5 - 2\(x\) = \(\dfrac{11}{14}\) : ( - \(\dfrac{11}{7}\))

4,5 - 2\(x\) = \(\dfrac{11}{14}\) \(\times\) (- \(\dfrac{7}{11}\))

4,5 - 2\(x\) = - \(\dfrac{1}{2}\) 

4,5 - 2\(x\) = -0,5

2\(x\) = 4,5 + 0,5

2\(x\) = 5

\(x\) = 5: 2

\(x\) = 2,5 

`a)(4,5-2x)*1 4/7=11/14`

`=>(4,5-2x)*11/7=11/14`

`=>4,5-2x=1/2`

`=>2x=4,5-0,5=4`

`=>x=2`

Vậy `x=2`

`b)(2,8x-32):2/3=-90`

`=>2,8x-32=-90*2/3=-60`

`=>2,8x=-28`

`=>x=-10`

Vậy `x=-10`

a, \(\left(2,8x-32\right):\dfrac{2}{3}=-90\)

\(\Rightarrow2,8x-32=-60\)

\(\Rightarrow2,8x=-28\)

\(\Rightarrow x=-10\)

Vậy x = -10

b, \(\left(4,5-2x\right):1\dfrac{4}{7}=\dfrac{11}{14}\)

\(\Rightarrow\left(4,5-2x\right):\dfrac{11}{7}=\dfrac{11}{14}\)

\(\Rightarrow4,5-2x=\dfrac{121}{98}\)

\(\Rightarrow2x=\dfrac{160}{49}\)

\(\Rightarrow x=\dfrac{80}{49}\)

Vậy \(x=\dfrac{80}{49}\)

\(a,\left(2,8x-32\right):\dfrac{2}{3}=-90\)

\(2,8x-32=-90.\dfrac{2}{3}\)

\(2,8x-32=-60\)

\(2,8x=-60+32\)

\(2,8x=-28\)

\(x=-28:2,8\)

\(x=-10\)

Vậy \(x=-10\)

\(b,\left(4,5-2x\right):1\dfrac{4}{7}=\dfrac{11}{14}\)

\(\left(4,5-2x\right):\dfrac{11}{7}=\dfrac{11}{14}\)

\(4,5-2x=\dfrac{11}{14}.\dfrac{11}{7}\)

\(4,5-2x=\dfrac{121}{98}\)

\(2x=4,5-\dfrac{121}{98}\)

\(2x=\dfrac{160}{49}\)

\(x=\dfrac{160}{49}:2\)

\(x=\dfrac{80}{49}\)

Vậy \(x=\dfrac{80}{49}\)

\(a,\left(2,8x-32\right):\dfrac{2}{3}=-90\)

\(2,8x-32\) \(=-90.\dfrac{2}{3}\)

\(2,8x-32\)

a) \(\dfrac{x+1}{32}=\dfrac{2}{x+1}\)

\(\Leftrightarrow\dfrac{x+1}{32}=\dfrac{2}{x+1}\left(đk:x\ne1\right)\)

\(\Leftrightarrow\left(x+1\right)\left(x+1\right)=64\)

\(\Leftrightarrow\left(x+1\right)^2-64=0\)

\(\Leftrightarrow x^2+2x+1-64=0\)

\(\Leftrightarrow x^2+6x-63=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-2+16}{2}\\x=\dfrac{-2-16}{2}\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-9\end{matrix}\right.\left(đk:x\ne-1\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-9\end{matrix}\right.\)

Vậy \(x_1=-9;x_2=7\)

b) \(\dfrac{x+1}{5}=\dfrac{7}{x-1}\)

\(\Leftrightarrow\dfrac{x+1}{5}=\dfrac{7}{x-1}\left(đk:x\ne1\right)\)

\(\Leftrightarrow\left(x+1\right)\left(x-1\right)=35\)

\(\Leftrightarrow\left(x+1\right)\left(x-1\right)-35=0\)

\(\Leftrightarrow x^2-1-35=0\)

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

\(\Leftrightarrow x^2=36\)

\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\left(đk:x\ne1\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)

Vậy \(x_1=-6;x_2=6\)

c) \(\left|4,5-2x\right|:1\dfrac{7}{4}=\dfrac{11}{14}\)

\(\Leftrightarrow\left|4,5-2x\right|:\dfrac{11}{4}=\dfrac{11}{4}\)

\(\Leftrightarrow\left|4,5-2x\right|\cdot\dfrac{4}{11}=\dfrac{11}{14}\)

\(\Leftrightarrow\dfrac{4}{11}\cdot\left|4,5-2x\right|=\dfrac{11}{14}\)

\(\Leftrightarrow\left|4,5-2x\right|=\dfrac{121}{56}\)

\(\Leftrightarrow\left[{}\begin{matrix}4,5-2x=\dfrac{121}{56}\\4,5-2x=-\dfrac{121}{56}\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{131}{112}\\x=\dfrac{373}{112}\end{matrix}\right.\)

Vậy \(x_1=\dfrac{131}{112};x_2=\dfrac{373}{112}\)

a) \(\dfrac{x+1}{32}=\dfrac{2}{x+1}\)

\(\Rightarrow\left(x+1\right)\left(x+1\right)=32.2\)

\(\Rightarrow\left(x+1\right)^2=64\)

\(\Rightarrow\left(x+1\right)^2=8^2\)

\(\Rightarrow x+1=8\)

\(\Rightarrow x=8-1\)

\(\Rightarrow x=7\left(TM\right)\)

Vậy \(x=7\) là giá trị cần tìm

b) \(\dfrac{x+1}{5}=\dfrac{7}{x-1}\)

\(\Rightarrow\left(x+1\right)\left(x-1\right)=7.5\)

\(\Rightarrow\left[{}\begin{matrix}x+1=7\\x-1=5\end{matrix}\right.\) \(\Rightarrow x=6\left(TM\right)\)

Vậy \(x=6\) là giá trị cần tìm

c) \(\left|4,5-2x\right|:1\dfrac{7}{4}=\dfrac{11}{14}\)

\(\left|\dfrac{45}{10}-2x\right|:\dfrac{11}{4}=\dfrac{11}{4}\)

\(\left|\dfrac{9}{2}-2x\right|=\dfrac{11}{14}.\dfrac{11}{4}\)

\(\left|\dfrac{9}{2}-2x\right|=\dfrac{121}{56}\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{9}{2}-2x=\dfrac{121}{56}\\\dfrac{9}{2}-2x=\dfrac{-121}{56}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=\dfrac{131}{56}\\2x=\dfrac{373}{56}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{131}{112}\\x=\dfrac{373}{112}\end{matrix}\right.\)

Vậy \(x\in\left\{\dfrac{131}{112};\dfrac{373}{112}\right\}\) là giá trị cần tìm

b) x +1/5 = 7/x - 1

Suy ra: ( x+1).(x - 1) = 7.5

Nếu x +1= 7 Nếu x -1 = 5

X = 6 x = 6

Vậy x cần tìm là 6

Anh làm lại câu b)

\(\left(4,5-200\%x\right).1\dfrac{4}{7}=\dfrac{11}{14}\\ < =>\left(\dfrac{9}{2}-2x\right).\dfrac{11}{7}=\dfrac{11}{14}\\ =>\dfrac{9}{2}-2x=\dfrac{\dfrac{11}{14}}{\dfrac{11}{7}}=\dfrac{1}{2}\\ =>2x=\dfrac{9}{2}-\dfrac{1}{2}=4\\ =>x=\dfrac{4}{2}=2\)

a, \(3x+\dfrac{1}{8}=2\dfrac{3}{4}\\ < =>3x+\dfrac{1}{8}=\dfrac{11}{4}\\ =>3x=\dfrac{11}{4}-\dfrac{1}{8}=\dfrac{21}{8}\\ =>x=\dfrac{\dfrac{21}{8}}{3}=\dfrac{7}{8}\)

b, \(\left(4,5-200\%x\right).1\dfrac{4}{7}=\dfrac{11}{14}\\ < =>\left(4,5-2x\right).\dfrac{11}{7}=\dfrac{11}{4}\\ =>4,5-2x=\dfrac{11}{4}:\dfrac{11}{7}=\dfrac{7}{4}\\ =>2x=4,5-\dfrac{7}{4}=\dfrac{11}{4}\\ =>x=\dfrac{\dfrac{11}{4}}{2}=\dfrac{11}{8}\)

a) 3x + \(\dfrac{1}{8}\) = \(2\dfrac{3}{4}\)

3x + \(\dfrac{1}{8}=\dfrac{11}{4}\)

3x \(=\dfrac{11}{4}-\dfrac{1}{8}=\dfrac{21}{8}\)

x \(=\dfrac{21}{8}:3=\dfrac{7}{8}\)

Vậy x = \(\dfrac{7}{8}\).

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(4,5 - \(2\)x) . \(\dfrac{11}{7}\) = \(\dfrac{11}{14}\)

(4,5 - 2x) \(=\dfrac{11}{14}:\dfrac{11}{7}=\dfrac{1}{2}\)

2x \(=4,5-\dfrac{1}{2}=4\)

x \(=4:2=2\)

Vậy x = 2.