0,2x(x-3)=(x-3)(1,8-3)
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a) \(1,25:0,8=\frac{3}{8}:0,2x\)
\(\Rightarrow\frac{3}{8}:0,2x=\frac{25}{16}\)
\(\Rightarrow0,2x=\frac{3}{8}:\frac{25}{16}=\frac{6}{25}\)
\(\Rightarrow x=\frac{6}{25}:\frac{1}{5}=\frac{6}{5}\)
b) \(1,8:1,3=\left(-2,7\right):5x\)
\(\Rightarrow\frac{-27}{10}:5x=\frac{18}{13}\)
\(\Rightarrow5x=\frac{-27}{10}:\frac{18}{13}=\frac{-39}{20}\)
\(\Rightarrow x=\frac{-39}{100}\)
Tính phải k nhỉ?
`1)`
`2x + 3x + 5x`
`= (2 + 3 + 5)x`
`= 10x`
`2)`
`2.x - x + 3.x`
`= (2 - 1 + 3)x`
`= 4x`
`3)`
`9.x - 3 - 3.x`
`= (9 - 3)x - 3`
`= 6x - 3`
`4)`
Thiếu dấu, bạn bổ sung thêm
`5)`
`x - 0,2x - 0,1x`
`= (1 - 0,2 - 0,1)x`
`=0,7x`
`6)`
\(\dfrac{7}{2}x-\dfrac{1}{2}x=\left(\dfrac{7}{2}-\dfrac{1}{2}\right)x=3x\)
a: =>x-2=0 hoặc x+3=0
=>x=2 hoặc x=-3
b:=>x-7=0 hoặc x+2=0
=>x=7 hoặc x=-2
c: =>4x+2=0 hoặc 3x-4=0
=>x=4/3 hoặc x=-1/2
d: =>2x+1=0 hoặc x-3=0
=>x=3 hoặc x=-1/2
a)
`(x-2)(x+3)=0`
`<=> x-2=0` hoặc `x+3=0`
`<=>x=2` hoặc `x=-3`
b)
`(x-7)(2+x)=0`
`<=>x-7=0` hoặc `2+x=0`
`<=>x=7` hoặc `x=-2`
c)
`(4x+2)(3x-4)=0`
`<=>4x+2=0` hoặc `3x-4=0`
`<=>x=-1/2` hoặc `x=4/3`
d)
`(2x+1)(x-3)=0`
`<=>2x+1=0` hoặc `x-3=0`
`<=>x=-1/2` hoặc `x=3`
e)
`(0,1x-3)(x+0,5)=0`
`<=>0,1x-3=0` hoặc `x+0,5=0`
`<=>x=30` hoặc `x=-0,5`
f)
`(0,2x-0,4)(0,1x+0,7)=0`
`<=>0,2x-0,4=0` hoặc `0,1x+0,7=0`
`<=>x=2` hoặc `x=-7`
\(a.12-\left|x-3\right|=5x+\)\(8\)
\(\Leftrightarrow\left|x-3\right|=5x+8-12\)
\(\Leftrightarrow\left|x-3\right|=5x-4\)
\(\Leftrightarrow\orbr{\begin{cases}x-3=5x-4\\x-3=-5x+4\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{1}{4}\\x=\frac{7}{6}\end{cases}}}\)
\(b.3-\frac{0.2x}{5}=\frac{7}{15}+1,4x\)
\(\Leftrightarrow\frac{15-0,2x}{5}=\frac{7+21x}{15}\)
\(\Leftrightarrow15.\left(15-0,2x\right)=5.\left(7+21x\right)\)
\(\Leftrightarrow225-3x=35+105x\)
\(\Leftrightarrow-3x-105x=35-225\)
\(\Leftrightarrow-108x=-190\)
\(\Rightarrow x=\frac{95}{54}\)
\(\dfrac{1}{5}x-\dfrac{2}{3}x-\dfrac{2}{3}-\dfrac{1}{3}=0\)
\(\Leftrightarrow\dfrac{-7}{15}x-1=0\)
\(\Leftrightarrow\dfrac{-7x}{15}=1\)
\(\Leftrightarrow x=\dfrac{-15}{7}\)
0,2x - \(\dfrac{2}{3}x\)- \(\dfrac{2}{3}\)=\(\dfrac{1}{3}\)
<=> \(\dfrac{-1,4}{3}\)x=1
<=> x = \(\dfrac{-3}{1,4}\)
\(\dfrac{1}{2}x+0,2x-x-\dfrac{1}{5}=2\dfrac{3}{5}\\ \dfrac{1}{2}x+0,2x-x-\dfrac{1}{5}=\dfrac{13}{5}\\ x\cdot\left(\dfrac{1}{2}+0,2-1\right)=\dfrac{14}{5}\\ x\cdot\left(\dfrac{5}{10}+\dfrac{2}{10}+\dfrac{10}{10}\right)=\dfrac{14}{5}\\ x\cdot\dfrac{17}{10}=\dfrac{14}{5}\\ x=\dfrac{14}{5}:\dfrac{17}{10}\\ x=\dfrac{14}{5}\cdot\dfrac{10}{17}\\ x=\dfrac{28}{17}\)
\(\Leftrightarrow\dfrac{x}{5}\left(x-3\right)-\left(x-3\right)\left(-\dfrac{6}{5}\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(\dfrac{x}{5}+\dfrac{6}{5}\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(\dfrac{x+6}{5}\right)=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-3=0\\\dfrac{x+6}{5}=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0+3\\x=\left(0:5\right)-6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\x=-6\end{matrix}\right.\)