tìm x biết
\(\dfrac{x}{27}\)=\(\dfrac{-2}{3,6}\)
Tìm \(x\) trong các tỉ lệ thức sau :
a) \(\dfrac{x}{27}=\dfrac{-2}{3,6}\)
b) \(-0,52:x=-9,36:16,38\)
c) \(\dfrac{4\dfrac{1}{4}}{2\dfrac{7}{8}}=\dfrac{x}{1,61}\)
a) \(\dfrac{x}{27}=\dfrac{-2}{3,6}\)
=> x. 3,6 = 27. (-2)
=> x.3,6 = -54
x = (-54) : 3,6
x = -15
b) -0,52 : x = -9,36 : 16,38
- 0,52 : x = \(\dfrac{-4}{7}\)
x = \(\dfrac{-4}{7}\) . ( -0,52)
x = \(\dfrac{52}{175}\)
Lời giải:
a)
b)
-0,52 : x = -9,36: 16,38 => -0,52 . 16,38 = x. (-9,36) => x = -8,5176: ( -9,36) => x = 0,91
c)
a)\(\dfrac{x}{27}=\dfrac{-2}{3,6}\)
=>x.3,6=27.(-2)
=>x . 3,6=-54
=>x=-54:3.6
=>x=-54:\(\dfrac{18}{5}\)
=>x=-54.\(\dfrac{5}{18}\)
=>x=-15
b)-0,52:x=-9,36:16,38
-\(\dfrac{13}{25}:x=-\dfrac{234}{25}:\dfrac{819}{50}\)
\(-\dfrac{13}{25}:x=-\dfrac{4}{7}\)
\(x=-\dfrac{4}{7}:\left(-\dfrac{13}{25}\right)\)
x=\(\dfrac{52}{175}\)
c)\(\dfrac{4\dfrac{1}{4}}{2\dfrac{7}{8}}=\dfrac{x}{1,61}\)
\(\dfrac{\dfrac{17}{4}}{\dfrac{23}{8}}=\dfrac{x}{1,61}\)
\(\dfrac{17}{4}:\dfrac{23}{8}=\dfrac{x}{1,61}\)
\(\dfrac{17}{4}.\dfrac{8}{23}=\dfrac{x}{1,61}\)
\(\dfrac{34}{23}=\dfrac{x}{1,61}\)
=>34.1,61=x.23
rồi bạn tự tính tự làm nốt nhé
Tìm x biết: a) x + \(\dfrac{2}{3}=\dfrac{4}{27}\) b) \(\dfrac{3}{4}x-\dfrac{7}{3}=\dfrac{1}{4}x+\dfrac{1}{6}\)
c) \(\dfrac{13}{10}x-\dfrac{5}{2}=\dfrac{7}{2}\) d) (3\(x\) + 2) \(\left(\dfrac{-2}{5}x-7\right)=0\)
a: x=4/27-2/3=4/27-18/27=-14/27
b: =>3/4x-1/4x=1/6+7/3
=>1/2x=1/6+14/6=5/2
hay x=5
c: =>13/10x=7/2+5/2=6
=>x=13/10:6=13/60
d: (3x+2)(-2/5x-7)=0
=>3x+2=0 hoặc 2/5x+7=0
=>x=-2/3 hoặc x=-35/2
a: x=4/27-2/3=4/27-18/27=-14/27
b: =>3/4x-1/4x=1/6+7/3
=>1/2x=1/6+14/6=5/2
hay x=5
c: =>13/10x=7/2+5/2=6
=>x=13/10:6=13/60
d: (3x+2)(-2/5x-7)=0
=>3x+2=0 hoặc 2/5x+7=0
=>x=-2/3 hoặc x=-35/2
tìm x ∈ Q biết : \(\dfrac{3\left(x+1\right)}{2}\)=\(\dfrac{8}{27\left(x-1\right)}\)
tìm x biết
\(\dfrac{7}{9}:\left(2+\dfrac{3}{4}.x\right)+\dfrac{5}{9}=\dfrac{23}{27}\)
|x|\(-\dfrac{3}{4}=\dfrac{5}{3}\)
\(\left|2.x-\dfrac{1}{3}\right|+\dfrac{5}{6}=1\)
giúp mk vs nhanh lên mình đang bận
b) Ta có: \(\left|x\right|-\dfrac{3}{4}=\dfrac{5}{3}\)
\(\Leftrightarrow\left|x\right|=\dfrac{5}{3}+\dfrac{3}{4}=\dfrac{20}{12}+\dfrac{9}{12}=\dfrac{29}{12}\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{29}{12}\\x=-\dfrac{29}{12}\end{matrix}\right.\)
c) Ta có: \(\left|2x-\dfrac{1}{3}\right|+\dfrac{5}{6}=1\)
\(\Leftrightarrow\left|2x-\dfrac{1}{3}\right|=\dfrac{1}{6}\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-\dfrac{1}{3}=\dfrac{1}{6}\\2x-\dfrac{1}{3}=\dfrac{-1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{1}{6}+\dfrac{1}{3}=\dfrac{1}{2}\\2x=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{4}\\x=\dfrac{1}{12}\end{matrix}\right.\)
tìm x biết :\(\dfrac{6}{x}=\dfrac{24}{x-27}\)
\(\dfrac{6}{x}=\dfrac{24}{x-7}\left(x\ne0;x\ne27\right)\)
suy ra
`6(x-27)=24x`
`=>6x-162-24x=0`
`=>-18x=162`
`=>x=-9(tm)`
\(\dfrac{6}{x}=\dfrac{24}{x-27}\left(dkxd:x\ne0,x\ne27\right)\)
\(\Leftrightarrow\dfrac{6}{x}-\dfrac{24}{x-27}=0\)
\(\Leftrightarrow\dfrac{6\left(x-27\right)-24x}{x\left(x-27\right)}=0\)
\(\Leftrightarrow6x-162-24x=0\)
\(\Leftrightarrow-18x=162\)
\(\Leftrightarrow x=--9\)
`6/x = 24/(x-27)`
`=> 6 (x-27)= 24x`
`=> 6x - 162=24x`
`=> 6x - 24x=162`
`=>-18x=162`
`=>x=162 :(-18)`
`=>x=-9`
tìm x
a/\(\dfrac{x}{2}=\dfrac{32}{x}\)
b/\(\dfrac{5}{25}=5\)
c/\(\dfrac{30^x}{27^x}=27\)
d/5x . 10x=2500
Tìm x ∈ N biết :
a) \(8< 2^x\le2^9.2^{-5}\)
b)\(27< 81^3:3^x< 243\)
c)\(\left(\dfrac{2}{5}\right)^x>\left(\dfrac{5}{2}\right)^{-3}.\left(\dfrac{-3}{5}\right)^2\)
\(a,\Rightarrow2^3< 2^x\le2^4\Rightarrow x=4\\ b,\Rightarrow3^3< 3^{12}:3^x< 3^5\\ \Rightarrow3^3< 3^{12-x}< 3^5\\ \Rightarrow12-x=4\Rightarrow x=8\)
x2 - \(\dfrac{3}{7}.\dfrac{35}{27}=\dfrac{11}{9}\)
Tìm x, biết
Bài 4. Tìm x biết:
a. \(\dfrac{x}{5}=\dfrac{2}{5},\dfrac{3}{8}=\dfrac{6}{x},\dfrac{1}{9}=\dfrac{x}{27}\)
b. \(\dfrac{4}{x}=\dfrac{8}{6},\dfrac{3}{x-5}=\dfrac{-4}{x+2},\dfrac{x}{-2}=\dfrac{-8}{x}\)
a,2/5 = 2/5 ; 3/8=6/16 ; 1/9=3/27
b, 4/3=8/6 ; -1=-1 ; -4/-2=-8/4
tick cho mik nhé
a) x= 2, x= 8.(6 : 3) = 16, x= 1. (27 : 9)= 3
b) x= 6 : (8 : 4) = 3, x= -1, x= -2 . -8 = x.x => 16 = x2 => 42 = x2 => x=4
Tick cho mình đi