Tìm x:
4,5 - 2x .\(1\dfrac{4}{7}\) =\(\dfrac{11}{14}\)
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LS
5
8 tháng 3 2022
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
NH
3
O
12 tháng 5 2022
\(\left(4,5-2x\right)\cdot1\dfrac{4}{7}=\dfrac{11}{14}\)
\(\left(\dfrac{9}{2}-2x\right)\cdot\dfrac{11}{7}=\dfrac{11}{14}\)
\(\dfrac{9}{2}-2x=\dfrac{11}{14}:\dfrac{11}{7}\)
\(\dfrac{9}{2}-2x=\dfrac{1}{2}\)
\(2x=\dfrac{9}{2}-\dfrac{1}{2}\)
\(2x=\dfrac{8}{2}\)
\(x=\dfrac{8}{2}:2\)
`x=2`
LA
1
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
1 tháng 5 2023
(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
16 tháng 7 2021
`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`
17 tháng 4 2017
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 \(x=\dfrac{80}{49}\)
C
17 tháng 4 2017
\(a,\left(2,8x-32\right):\dfrac{2}{3}=-90\)
\(2,8x-32=-90.\dfrac{2}{3}\)
\(2,8x-32=-60\)
\(2,8x=-60+32\)
\(2,8x=-28\)
\(x=-28:2,8\)
\(x=-10\)
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 \(x=\dfrac{80}{49}\)
Q
21 tháng 6 2017
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 \(x_1=\dfrac{131}{112};x_2=\dfrac{373}{112}\)
21 tháng 6 2017
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
26 tháng 5 2017
Anh làm lại câu b)
\(\left(4,5-200\%x\right).1\dfrac{4}{7}=\dfrac{11}{14}\\ < =>\left(\dfrac{9}{2}-2x\right).\dfrac{11}{7}=\dfrac{11}{14}\\ =>\dfrac{9}{2}-2x=\dfrac{\dfrac{11}{14}}{\dfrac{11}{7}}=\dfrac{1}{2}\\ =>2x=\dfrac{9}{2}-\dfrac{1}{2}=4\\ =>x=\dfrac{4}{2}=2\)
26 tháng 5 2017
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, \(\left(4,5-200\%x\right).1\dfrac{4}{7}=\dfrac{11}{14}\\ < =>\left(4,5-2x\right).\dfrac{11}{7}=\dfrac{11}{4}\\ =>4,5-2x=\dfrac{11}{4}:\dfrac{11}{7}=\dfrac{7}{4}\\ =>2x=4,5-\dfrac{7}{4}=\dfrac{11}{4}\\ =>x=\dfrac{\dfrac{11}{4}}{2}=\dfrac{11}{8}\)
\(4,5-2x.1\dfrac{4}{7}=\dfrac{11}{14}\)
<=>\(-\dfrac{22}{7}x=\)\(\dfrac{11}{14}-4,5\)
<=>\(-\dfrac{22}{7}x=-\dfrac{26}{7}\)
<=>\(x=-\dfrac{26}{7}:\left(-\dfrac{22}{7}\right)\)
<=>\(x=\dfrac{13}{11}\)
4,5 -2x.11/7=11/4
2x.11/7=4.5-11/4
2x.11/7=7/4
2x =7/4: 11/7
2x=49/44
x=49/44: 2
x=49/88