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3 tháng 2 2022
a) \(\dfrac{-x}{4}=\dfrac{-9}{x}\)
\(\Rightarrow-x^2=-36\)
\(\Rightarrow x^2=36\)
\(\Rightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
Vậy: \(x\in\left\{6;-6\right\}\)
b) \(\dfrac{5}{9}+\dfrac{x}{-1}=-\dfrac{1}{3}\)
\(\Rightarrow\dfrac{5}{9}+\dfrac{-9x}{9}=\dfrac{-3}{9}\)
\(\Rightarrow5-9x=-3\)
\(\Rightarrow-9x=-8\)
\(\Rightarrow x=\dfrac{8}{9}\)
Vậy: \(x=\dfrac{8}{9}\)
c) \(x:3\dfrac{1}{5}=1\dfrac{1}{2}\)
\(\Rightarrow x:\dfrac{16}{5}=\dfrac{3}{2}\)
\(\Rightarrow x=\dfrac{3}{2}.\dfrac{16}{5}\)
\(\Rightarrow x=\dfrac{24}{5}\)
Vậy: \(x=\dfrac{24}{5}\)
d) \(\dfrac{3x-1}{-5}=\dfrac{-5}{3x-1}\)
\(\Rightarrow\left(3x-1\right)^2=25\)
\(\Rightarrow\left[{}\begin{matrix}3x-1=5\\3x-1=-5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}3x=6\\3x=-4\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{4}{3}\end{matrix}\right.\)
Vậy: \(x\in\left\{2;-\dfrac{4}{3}\right\}\)
13 tháng 10 2021
\(a,\Rightarrow\left(35x+3\right)\cdot19=152\\ \Rightarrow35x+3=8\\ \Rightarrow x=\dfrac{1}{7}\\ b,\Rightarrow3\left(x+7\right)=42\\ \Rightarrow x+7=14\Rightarrow x=7\\ c,\Rightarrow3\left(x+1\right)=48\\ \Rightarrow x+1=16\Rightarrow x=15\\ d,\Rightarrow120-5x+100\cdot2:5=4\cdot15\\ \Rightarrow120-5x+40=60\\ \Rightarrow5x=100\Rightarrow x=20\\ e,\Rightarrow4x-10=30\\ \Rightarrow4x=40\\ \Rightarrow x=10\\ g,\Rightarrow10x+10=70\\ \Rightarrow10x=60\\ \Rightarrow x=6\)
DN
2
NA
20 tháng 12 2021
a. 4.(x+41) = 7
x + 41 = 7 : 4 = 1,75
x = 1,75 - 41 = -39,25
b. 4.(x-3) = 72 - 110 = 49 - 1 = 48
x - 3 = 48 : 4 = 12
x = 12 + 3 = 15
DN
3
20 tháng 12 2021
a) \(4\left(x+41\right)=400\)
\(\Rightarrow x+41=400:4\)
\(\Rightarrow x+41=100\)
\(\Rightarrow x=100-41\)
\(\Rightarrow x=59\)
18 tháng 1
b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)
=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)
=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)
=>\(x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=-\dfrac{2}{3}\)
=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)
=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)
=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)
d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)
=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)
=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)
=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)
5 tháng 5 2021
c) Ta có: \(\left|x-\dfrac{2}{3}\right|+2.25=\dfrac{3}{4}\)
\(\Leftrightarrow\left|x-\dfrac{2}{3}\right|=\dfrac{3}{4}-\dfrac{9}{4}=\dfrac{-3}{2}\)(vô lý)
Vậy: \(x\in\varnothing\)
5 tháng 5 2021
a) Ta có: \(x+\dfrac{-3}{7}=\dfrac{4}{7}\)
\(\Leftrightarrow x-\dfrac{3}{7}=\dfrac{4}{7}\)
hay x=1
Vậy: x=1
Y
31 tháng 5 2023
\(a,50\%x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x+x=\dfrac{4}{5}+0,2\)
\(\Leftrightarrow\dfrac{3}{2}x=\dfrac{4}{5}+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{3}{2}x=1\)
\(\Leftrightarrow x=\dfrac{2}{3}\)
\(b,\left(x-\dfrac{3}{4}\right):\dfrac{1}{2}+\dfrac{3}{2}=\dfrac{25}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{25}{2}-\dfrac{3}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{22}{2}\)
\(\Leftrightarrow x-\dfrac{3}{4}=11:2\)
\(\Leftrightarrow x=\dfrac{11}{2}+\dfrac{3}{4}\)
\(\Leftrightarrow x=\dfrac{25}{4}\)
KV
21 tháng 4 2022
a) \(\left(12-12\dfrac{1}{3}\right):x+\dfrac{1}{6}=-\dfrac{2}{3}\)
\(-\dfrac{1}{3}x=-\dfrac{2}{3}-\dfrac{1}{6}\)
\(-\dfrac{1}{3}x=-\dfrac{5}{6}\)
\(x=-\dfrac{5}{6}:\left(-\dfrac{1}{3}\right)\)
\(x=\dfrac{5}{2}\)
b) \(\dfrac{4}{x}=\dfrac{x}{16}\)
\(x^2=4.16\)
\(x^2=64\)
\(\Rightarrow x=8;x=-8\)
NA
21 tháng 4 2022
`a)=>(12-37/3):x+1/6=-2/3`
`=>(12-37/3):x=-5/6`
`=>(-1/3):x=-5/6`
`=>x=(-1/3):(-5/6)`
`=>x=6/15=2/5`
`b)4/x=x/16`
`=>x^2=4*16`
`=>x^2=64`
`=>x^2=(+-8)^2`
a, Ta có: \(|x-1|\ge0\forall x;|x-4|\ge0\forall x\)
\(\Rightarrow|x-1|+|x-4|\ge0\forall x\)
\(\Rightarrow3x\ge0\)
\(\Rightarrow x-1+x-4=3x\)
\(\Rightarrow\left(x+x\right)-\left(1+4\right)=3x\)
\(\Rightarrow2x-5=3x\)
\(\Rightarrow3x-2x=5\)
\(\Rightarrow x=5\)
Vậy x=5
b, Ta có: \(|x+1|\ge0\forall x;|x+4|\ge0\forall x\)
\(\Rightarrow|x+1|+|x+4|\ge0\)
\(\Rightarrow3x\ge0\)
\(\Rightarrow\left(x+1\right)+\left(x+4\right)=3x\)
\(\Rightarrow x+1+x+4=3x\)
\(\Rightarrow\left(x+x\right)+\left(1+4\right)=3x\)
\(\Rightarrow2x+5=3x\)
\(\Rightarrow5=3x-2x\)
\(\Rightarrow5=x\)
Vậy x=5
a) Lập bảng xét dấu, ta được kết quả sau:
Nếu \(x\le1\Rightarrow\left|x-1\right|+\left|x-4\right|=-\left(x-1\right)-\left(x-4\right)=3x\)
\(=-x+1-x+4=3x\Rightarrow-5x=-5\Rightarrow x=1\) (nhận)
Nếu \(1\le x< 4\Rightarrow\left|x-1\right|+\left|x-4\right|=x-1-x+4=3x\)
\(-3x=-3\Rightarrow x=1\) (nhận)
Nếu \(x\ge4\Rightarrow\left|x-1\right|+\left|x-4\right|=x-1+x-4=3x\)
\(\Rightarrow-x=5\Rightarrow x=-5\) (loại)
Vậy x = 1