4(10:2-7:l-7l)-5 (-5):2
3(-5:5-4)-l-3l(-5)
-2(-3+l-8l:2-7) -5l-4l
Tìm x biết
a, l x+2 l + l2x-3l =5
b, 3.(2x-1) - lx-5l =7
c, l 2x-1l - 2x =3
d, 3x - l 2-3xl = 2
e, lx-4l + lx+5l =9
1) Tính
a) (-3)x (15-14+17-18) x l-1250l x (-87)
b) (-3+8)x (-5-3)x (-5+l+2l-l-2 l
c) (-7+5) x (4-l-7l+l+2l x (-3+l-5l)
Tìm x , biết
d) \(\left(3x-2^4\right).7^3=2.7^4\)
e) x - [ 42 + ( -28 ) ] = -8
g) x - 7 = -5
h) 15 - 5( x + 4 ) = -12 - 3
i) ( 7 - x ) - ( 25 + 7 ) = -25
k) l x + 2 l = 0
l) l x - 3 l = 7 - ( -2 )
m) lx - 5l = l-7l
d, \(\left(3x-2^4\right).7^3=2.7^4\)
\(\Rightarrow3x-2^4=2.7^4:7^3\)
\(\Rightarrow3x-16=2.7\\ \Rightarrow3x=14+16\\ \Rightarrow3x=30\Rightarrow x=10\)
Vậy.....
e, \(x-\left[42+\left(-28\right)\right]=-8\)
\(\Rightarrow x-14=-8\\ \Rightarrow x=6\)
Vậy.....
g, \(x-7=-5\)
\(\Rightarrow x=-5+7\Rightarrow x=2\)
Vậy.....
h, \(15-5\left(x+4\right)=-12-3\)
\(\Rightarrow15-5x-20=-15\)
\(\Rightarrow-5x=-15-15+20\)
\(\Rightarrow-5x=-10\Rightarrow x=2\)
Vậy.....
Chúc bạn học tốt!!!
d/ \(\left(3x-2^4\right)\cdot7^3=2\cdot7^4\)
\(\Rightarrow3x-16=\dfrac{2\cdot7^4}{7^3}=14\)
\(\Rightarrow3x=14+16=30\)
\(\Rightarrow x=\dfrac{30}{3}=10\)
e/ Đễ ==> tự lm thì tốt hơn nhé
g/ Đễ ==> tự lm thì tốt hơn nhé
h/ \(15-5\left(x+4\right)=-12-3\)
\(\Rightarrow15-5x-20=-15\)
\(\Rightarrow-5x=-15+20-15=-10\)
\(\Rightarrow x=\dfrac{-10}{-5}=2\)
i/ \(\left(7-x\right)-\left(25+7\right)=-25\)
\(\Rightarrow7-x-25-7=-25\)
\(\Rightarrow-x=-25-7+7+25\)
\(\Rightarrow-x=0\Rightarrow x=0\)
k/ \(\left|x+2\right|=0\Rightarrow x+2=0\Rightarrow x=-2\)
l/ \(\left|x-3\right|=7-\left(-2\right)\)
\(\Rightarrow\left|x-3\right|=9\)
\(\Rightarrow\left[{}\begin{matrix}x-3=9\\x-3=-9\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=12\\x=-6\end{matrix}\right.\)
m/ \(\left|x-5\right|=\left|-7\right|\Rightarrow\left|x-5\right|=7\)
\(\Rightarrow\left[{}\begin{matrix}x-5=7\\x-5=-7\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=12\\x=-2\end{matrix}\right.\)
i, \(\left(7-x\right)-\left(25+7\right)=-25\)
\(\Rightarrow7-x-25-7=-25\)
\(\Rightarrow-x=-25-7+25+7\)
\(\Rightarrow x=0\)
Vậy.....
k, \(\left|x+2\right|=0\)
\(\Rightarrow x+2=0\Rightarrow x=-2\)
Vậy.....
l, \(\left|x-3\right|=-7-\left(-2\right)\)
\(\Rightarrow\left|x-3\right|=-5\)
Với mọi giá trị của \(x\in Z\) ta có:
\(\left|x-3\right|\ge0\) mà \(-5< 0\) nên không tìm được giá trị nào của x thoả mãn \(\left|x-3\right|=-5\).
Vậy \(x\in\varnothing\)
m, \(\left|x-5\right|=\left|-7\right|\)
\(\Rightarrow\left|x-5\right|=7\\ \Rightarrow\left\{{}\begin{matrix}x-5=-7\\x-5=7\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=-2\\x=12\end{matrix}\right.\)
Vậy...,..
Chúc bạn học tốt!!!
Tìm x biết
a, l x+2 l + l2x-3l =5
b, 3.(2x-1) - lx-5l =7
c, l 2x-1l - 2x =3
d, 3x - l 2-3xl = 2
e, lx-4l + lx+5l =9
Cần gấp.....m.n ai onl giúp với
\(c)\) \(\left|2x-1\right|-2x=3\)
\(\Leftrightarrow\)\(\left|2x-1\right|=2x+3\)
Ta có : \(\left|2x-1\right|\ge0\)
\(\Rightarrow\)\(2x+3\ge0\)\(\Rightarrow\)\(2x\ge-3\)\(\Rightarrow\)\(x\ge\frac{-3}{2}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}2x-1=2x+3\\2x-1=-2x-3\end{cases}\Leftrightarrow\orbr{\begin{cases}2x-2x=3+1\\2x+2x=-3+1\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}0=4\\4x=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}0=4\left(loai\right)\\x=\frac{-1}{2}\left(tm\right)\end{cases}}}\)
Vậy \(x=\frac{-1}{2}\)
Chúc bạn học tốt ~
\(b)\) \(3\left(2x-1\right)-\left|x-5\right|=7\)
\(\Leftrightarrow\)\(3\left(2x-1\right)-7=\left|x-5\right|\)
\(\Leftrightarrow\)\(6x-3-7=\left|x-5\right|\)
\(\Leftrightarrow\)\(\left|x-5\right|=6x-10\)
Ta có : \(\left|x-5\right|\ge0\)
\(\Rightarrow\)\(6x-10\ge0\)\(\Rightarrow\)\(6x\ge10\)\(\Rightarrow\)\(x\ge\frac{5}{3}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x-5=6x-10\\x-5=10-6x\end{cases}\Leftrightarrow\orbr{\begin{cases}6x-x=-5+10\\x+6x=10+5\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}5x=5\\7x=15\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\left(loai\right)\\x=\frac{15}{7}\left(tm\right)\end{cases}}}\)
Vậy \(x=\frac{15}{7}\)
Chúc bạn học tốt ~
Tìm x biết
a, l x+2 l + l2x-3l =5
b, 3.(2x-1) - lx-5l =7
c, l 2x-1l - 2x =3
d, 3x - l 2-3xl = 2
e, lx-4l + lx+5l =9
Đang cần gấp nhớ m.n giúp đỡ ạ
a: Trường hợp 1: x<-2
Pt sẽ là -x-2+3-2x=5
=>-3x+1=5
=>-3x=4
hay x=-4/3(loại)
Trường hợp 2: -2<=x<3/2
Pt sẽ là x+2+3-2x=5
=>5-x=5
hay x=0(nhận)
Trường hợp 2: x>=3/2
Pt sẽ là x+2+2x-3=5
=>3x-1=5
hay x=2(nhận)
b: \(\Leftrightarrow\left|x-5\right|=6x-3-7=6x-10\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=\dfrac{5}{3}\\\left(6x-10-x+5\right)\left(6x-10+x-5\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=\dfrac{5}{3}\\\left(5x-5\right)\left(7x-15\right)=0\end{matrix}\right.\Leftrightarrow x=\dfrac{15}{7}\)
c: \(\Leftrightarrow\left|2x-1\right|=2x+3\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=-\dfrac{3}{2}\\\left(2x+3+2x-1\right)\left(2x+3-2x+1\right)=0\end{matrix}\right.\Leftrightarrow x=-\dfrac{1}{2}\)
d: =>|3x-2|=3x-2
=>3x-2>=0
hay x>=2/3
Bài 1: 1/6x+1/10x-4/15x+1=0
Bài 2: a/ l5/3xl=l-1/6l b/ l3/4x-3/4l-3/4=l-3/4l c/ lx+3/5l-lx-7/3l
Bài 1:
1/6x+1/10x-4/15x+1=0
(1/6+1/10-4/15)x+1=0
0x+1=0
0x=0-1
0x=-1
x=-1/0
ko tim đc x thỏa mãn yêu cầu
Bài 2
a/ l5/3xl=l-1/6l
l5/3xl=1/6
\(\Rightarrow\)5/3x=1/6 hoặc 5/3x=-1/6
TH1:5/3x=1/6 TH2:5/3x=-1/6
x=1/6:5/3 x=-1/6:5/3
x=1/10 x=-1/10
Vậy x\(\in\) {1/10 và -1/10}
a. l x + 2 l = 0
b. l x - 5 l= l-7l
c. l x - 3 l = 7 - (- 2)
d. ( 3.x - 24 ) . 7 = 2. 7
e. x - [ 42 + (-28) = -8
a; |\(x+2\)| = 0
\(x+2=0\)
\(x\) = - 2
Vậy \(x\) = - 2
b; |\(x-5\)| = |-7|
| \(x-5\) | = 7
\(\left[{}\begin{matrix}x=7\\x=-7\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=5+7\\x=-7+5\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=12\\x=-2\end{matrix}\right.\)
Vậy \(x=12\)
\(x=-2\)
Tìm x
a)x-7 =-5 b)128-3.(x+4)=23 c)[(6x-39):7.4=12 d)lx-3l=7-(-2)
e)lx-5l=l-7l f)x-[42+(-28)]=-8
Mọi người giúp mình nha!!!
b) 128 - 3 . ( x + 4 ) = 23
3 . ( x + 4 ) = 128 - 23
3 . ( x + 4 ) = 105
x + 4 = 105 : 3
x + 4 = 35
x = 35 - 4
x = 31
d) | x - 3 | = 7 - ( -2 )
| x - 3 | = 9
\(\orbr{\begin{cases}x-3=9\\x-3=-9\end{cases}}\)
\(\orbr{\begin{cases}x=9+3\\x=-9+3\end{cases}}\)
\(\orbr{\begin{cases}x=12\\x=-6\end{cases}}\)
Vậy: ...
Bài 1: Tìm x
a) 2(4x-8)-7(3+x)=l4l.(3-2)
b)8(x-l-7l)-6(x-2)=l-8l.6-50
Bài 2: Tính các tổng sau:
a)S=1-2+3-4+....+2005-2006
b)S=1-3+5-7+......+2001-2003
c)S=2-4+6-8+.....+2008-2010
Ai đúng mình tích cho
Mình làm bài 1, bài 2 bạn tự làm nhé!
Bài 1:
a) \(2\left(4x-8\right)-7\left(3+x\right)=\left|4\right|\left(3-2\right)\)
\(\Leftrightarrow2\left(4x-8\right)-7\left(3+x\right)=4.1\)
\(\Leftrightarrow2\left(4x-8\right)-7\left(3+x\right)=4\)
\(\Leftrightarrow8x-16-21-7x=4\)
\(\Leftrightarrow x-37=4\)
\(\Leftrightarrow x=4+37\)
\(\Leftrightarrow x=41\)
Vậy \(x=41\)
b) \(8\left(x-\left|-7\right|\right)-6\left(x-2\right)=\left|-8\right|.6-50\)
\(\Leftrightarrow8\left(x-7\right)-6\left(x-2\right)=\left|-8\right|.6-50\)
\(\Leftrightarrow8\left(x-7\right)-6\left(x-2\right)=8.6-50\)
\(\Leftrightarrow8\left(x-7\right)-6\left(x-2\right)=48-50\)
\(\Leftrightarrow8\left(x-7\right)-6\left(x-2\right)=-2\)
\(\Leftrightarrow8x-56-6x+12=-2\)
\(\Leftrightarrow2x-44=-2\)
\(\Leftrightarrow2x=-2+44\)
\(\Leftrightarrow2x=42\)
\(\Leftrightarrow x=42:2\)
\(\Leftrightarrow x=21\)
Vậy \(x=21\)