Tìm x :
| x - 3 | + | x - 5 | - 4x = - 28 .
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) \(128-3\left(x+4\right)=23\)
\(\Rightarrow3\left(x+4\right)=128-23\)
\(\Rightarrow3\left(x+4\right)=105\)
\(\Rightarrow x+4=35\)
\(\Rightarrow x=35-4\)
\(\Rightarrow x=31\)
b) \(\left[\left(4x+28\right)\cdot3+55\right]:5=35\)
\(\Rightarrow\left(4x+28\right)\cdot3+55=35\cdot5\)
\(\Rightarrow\left(4x+28\right)\cdot3+55=175\)
\(\Rightarrow\left(4x+28\right)\cdot3=120\)
\(\Rightarrow4x+28=40\)
\(\Rightarrow4x=12\)
\(\Rightarrow x=3\)
a, \(128-3\left(x+4\right)=23\)
\(=>3\left(x+4\right)=128-23\)
\(=>3\left(x+4\right)=105\)
\(=>x+4=105:3\)
\(=>x+4=35\)
\(=>x=35-4\)
\(=>x=31\)
b, \(\left[\left(4x+28\right).3+55\right]:5=35\)
\(=>\left(4x+28\right).3+55=35.5\)
\(=>\left(4x+28\right).3+55=175\)
\(=>\left(4x+28\right).3=175-55\)
\(=>\left(4x+28\right).3=120\)
\(=>4x+28=120:3\)
\(=>4x+28=40\)
\(=>4x=40-28\)
\(=>4x=12\)
\(=>x=12:4\)
\(=>x=3\)
\(#WendyDang\)
a) Ta có : ( x + 1 ).( 3 - x ) > 0
Th1 : \(\hept{\begin{cases}x+1>0\\3-x>0\end{cases}\Rightarrow\hept{\begin{cases}x>-1\\x>3\end{cases}\Rightarrow}x>3}\)
Th2 : \(\hept{\begin{cases}x+1< 0\\3-x< 0\end{cases}\Rightarrow\hept{\begin{cases}x< -1\\x< 3\end{cases}\Rightarrow}x< -1}\)
a: =>3(x+4)=115
=>x+4=115/3
hay x=103/3
b: =>\(8^3\cdot\left(12x-64\right)=4\cdot8^4\)
\(\Leftrightarrow12x-64=32\)
=>12x=96
hay x=8
c: \(\Leftrightarrow\left(4x+28\right)\cdot23+55=175\)
=>(4x+28)x23=120
=>4x+28=120/23
=>4x=-524/23
hay x=-131/23
a, 3(x+2)-6(x-5)=2(5-2x)
3x+6-6x+30=10-4x
3x+6-6x+30-10+4x=0
3x-6x+4x+6+30-10=0
x+26=0
x= -26
b, (-2x)(-4x)+28=100
8x2 + 28=100
8x2 = 72
x2 = 9
=> x=3 hoặc x= -3
a/ 3(x+2) - 6(x-5) = 2(5-2x)
<-> 3x+6-6x+30 = 10-4x
<-> x = -26
b/ (-2x)(-4x) + 28 = 100
<-> 8x = 72
<-> x = 9
[(4x+28).3+35]:5=35
(4x + 28 ).3+ 35 =35 . 5
(4x +28 ) .3 + 35 = 175
(4x +28 ) .3 = 175 -35
(4x + 28 ) .3 = 140
4x + 28 = 140 : 3
4x + 28 = 140/3
4x =140/3 - 28
4x = 56/3
x = 56/3 : 4
x = 14/3
Vậy x bằng 14/3
|5x-3| - 3x = 7
*Nếu \(x\ge\frac{3}{5}\)
5x - 3 - 3x = 7
2x = 10
x = 5 ( tm)
*Nếu \(x< \frac{3}{5}\)
3 - 5x - 3x = 7
-8x = 4
x = \(-\frac{1}{2}\)( tm )
Làm hơi khó nhìn , thông cảm. Mệt rùi :)
|x - 3| + |x - 5| - 4x = -28
*Nếu x < 3
3 - x + 5 - x - 4x = -28
-6x = -36
x = 6 ( loại do ko tm khoảng đang xét )
* nếu 3 < x < 5
x - 3 + 5 - x - 4x = -28
-4x = -30
x= \(\frac{15}{2}\) ( loại do ko tm khaongr đang xét )
*Nếu x > 5
x - 3 + x - 5 - 4x = -28
-2x = -20
x = 10 ( tm)
Vậy x =10
b, (2x) . (-4x) + 28 = 100
2x . -4x = 100 - 28
-8x2 = 72
x2 = 72 : -8
x2 = -9
=> \(x\in\varphi\)
Chắc z á :v ~
a, 3( x + 2) - 6( x - 5 ) = 2( 5 - 2x )
3x + 6 - 6x + 30 - 10 + 4x = 0
<=> x( 3 - 6 + 4 ) + 6 + 30 - 10 = 0
=> x + 6 + 30 - 10 = 0
=> x= -26
Ta co´ :
a, 3 . ( x + 2 ) - 6 . ( x - 5 ) = 2 . ( 5 - 2x )
. 3x + 6 - 6x + 30 = 10 - 4x
3x - 6x + 4x = 10 - 6 - 30
x = - 26
b, ( - 2x ) . ( - 4x ) + 28 = 100
8x + 28 = 100
8x = 100 - 28
8x = 72
x = 72 : 8
x = 9
c, 5x . ( - x )2 + 1 = 6
5x . ( - x ) . ( - x ) + 1 = 6
5x . [ ( - x ) . ( - x ) ] + 1 = 6
5x . 2x + 1 = 6
5x . 2x = 6 - 1
5x . 2x = 5
Kẻ bảng . Co´ 4 trường hợp laˋ 5x = 1 ; 2x = 5
5x = 5. ; 2x = 1
5x = - 1 ; 2x = - 5
5x = - 5 ; 2x = - 1
\(\left|x-3\right|+\left|x-5\right|-4x=-28\)
\(\Leftrightarrow\left|x-3\right|+\left|x-5\right|=-28+4x\)
Vì \(\left\{{}\begin{matrix}\left|x-3\right|\ge0\\\left|x-5\right|\ge0\end{matrix}\right.\)
\(\Rightarrow\left|x-3\right|+\left|x-5\right|\ge0\)
\(\Rightarrow-28+4x\ge0\)
\(\Rightarrow4x\ge28\)
\(\Rightarrow x\ge7\)
\(\Rightarrow\left\{{}\begin{matrix}\left|x-3\right|=x-3\\\left|x-5\right|=x-5\end{matrix}\right.\)
Khi ấy : \(\left|x-3\right|+\left|x-5\right|=x-3+x-5\)
\(\Rightarrow2x-8=-28+4x\)
\(\Rightarrow2x-4x=-28+8\)
\(\Rightarrow-2x=-20\)
\(\Rightarrow x=\left(-20\right):\left(-2\right)=10\)