(x+1)+(x+3)+(x+5)+...+(x+21)=0
Những câu hỏi liên quan
tìm x,y,z
a) 12/16=-x/4 =21/y-z/80
b) 1/3 . x+2/5.(x-1)=0
c) (2.x-3).(6-2.x)=0
d)-2/3-1/3.(2.x-5)=3/2
e)(3.x-1).(-1/2.x+5)=0
f) (2.x+3/5)^2-9/25=0
10 tháng 11 2021 lúc 16:36
Chọn câu trả lời đúng \(\left(2x+\dfrac{1}{5}\right)\left(-\dfrac{3}{5}x+\dfrac{4}{7}\right)=0\) thì:
A. x = \(\dfrac{-1}{10}\) hoặc x = \(\dfrac{20}{21}\)
B. x = \(\dfrac{20}{21}\)
C. x = \(-\dfrac{1}{10}\)
D. x = \(-\dfrac{20}{21}\)
a, 3-x=x-5 b, 7x+21=0 c, 0,25x+1,5=0 d, 6,36-5,3x=0
e, 3x+1=7x-11 f, 15-4x=6x+5 g, 2(x+1)=3+2x
h, 3(1-x)+4x-3 = 0
a: =>-2x=-8
hay x=4
b: =>7x=-21
hay x=-3
c: =>0,25x=-1,5
hay x=-6
d: =>5,3x=6,36
hay x=6/5
e: =>-4x=-12
hay x=3
f: =>-10x=-10
hay x=1
g: =>2x+2-3-2x=0
=>-1=0(vô lý)
h: =>3-3x+4x-3=0
=>x=0
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a,
\(3-x=x-5\\ \Leftrightarrow3x-x+5=0\Leftrightarrow2x+5=0\)
\(\Rightarrow x=-\dfrac{5}{2}\)
b, \(\Rightarrow x=-\dfrac{21}{7}=-3\)
c, \(\Leftrightarrow x=\left(0-1,5\right):0,25=-6\)
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a. <=> 2x=8 hay x=4
b.<=> x= -21/7 = -3
c. <=> x= -1,5/ 0,25=-6
d. <=> x= -6,36/-5,3=1,2
e.<=> 4x=12 hay x= 3
f. <=> 10x = 10 hay x = 1
g. <=> 2x +2 = 3 + 2x
<=> 2=3 ( vô lí )
h.<=> 3 - 3x + 4x -3 =0
<=> x=0
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Xem thêm câu trả lời
Tìm x :
a) x ( x - 1 ) - x^2 + 2x = 5
b) 4x ( 3x + 2 ) - 6x ( 2x + 5 ) + 21 ( x - 1 ) = 0
c) 2x( x + 1) - x^2 ( x + 2 ) + x^3 - x + 4 = 0
a) \(x\left(x-1\right)-x^2+2x=5\)
\(\Leftrightarrow x^2-x-x^2+2x=5\)
\(\Leftrightarrow x=5\)
b) \(4x\left(3x+2\right)-6x\left(2x+5\right)+21\left(x-1\right)=0\)
\(\Leftrightarrow12x^2+8x-12x^2-30x+21x-21=0\)
\(\Leftrightarrow-x=21\)
\(\Leftrightarrow x=-21\)
c) \(2x\left(x+1\right)-x^2\left(x+2\right)+x^3-x+4=0\)
\(\Leftrightarrow2x^2+2x-x^3-2x^2+x^3-x+4=0\)
\(\Leftrightarrow x=-4\)
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a) x ( x - 1 ) - x^2 + 2x = 5
=>x2-x-x2+2x=5
=>-x+2x=5
=>x=5
b) 4x ( 3x + 2 ) - 6x ( 2x + 5 ) + 21 ( x - 1 ) = 0
=>12x2+8x-12x2-30x-21+21x=0
=>-x-21=0
=>x=-21
c) 2x( x + 1) - x^2 ( x + 2 ) + x^3 - x + 4 = 0
=>2x2+2x-x3-2x2+x3-x+4=0
=>x+4=0
=>x=-4
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tìm x để:
1) 21 ( x-3) < 0
2) (- 2) (x+7) < 0
3) ( x2 + 1)(x - 5) < 0
4) -3 (8-x) (x2+ 7) không dương
5) (x + 3) ( x - 4) không âm
6) (x - 1) (x +2) < 0
[x+5/3].[x-5/4]=0
1/3+1/2;x=-4
3/4+1/4;x=2/5
-2/5+5/6.x=-4/15
3/7-1/21.x=1/3
\(\left(x+\frac{5}{3}\right)\left(x-\frac{5}{4}\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(x+\frac{5}{3}\right)=0\\\left(x-\frac{5}{4}\right)=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{5}{3}\\x=\frac{5}{4}\end{cases}}}\)
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\(\frac{1}{3}+\frac{1}{2}\div x=-4\)
\(\frac{1}{2}\div x=-4-\frac{1}{3}\)
\(\frac{1}{2}\div x=-\frac{13}{3}\)
\(x=-\frac{3}{26}\)
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Bài 1: Tìm x , biết:
1) x - 2 -6 12) 3 . | x - 1 | - 5 7
2) -5 . x - ( -3 ) 13 13) -12 . ( x - 5 ) + 7 . ( 3 - x ) 5
3) 15 - ( x - 7 ) -21 14) ( x - 2 ) . ( x + 4 ) 0
4) 3 .x + 17 2...
Đọc tiếp
Bài 1: Tìm x , biết:
1) x - 2 = -6 12) 3 . | x - 1 | - 5 = 7
2) -5 . x - ( -3 ) = 13 13) -12 . ( x - 5 ) + 7 . ( 3 - x ) = 5
3) 15 - ( x - 7 ) = -21 14) ( x - 2 ) . ( x + 4 ) = 0
4) 3 .x + 17 = 2 15) ( x - 2 ) . ( x + 15 ) = 0
5) 45 - ( x - 9 ) = -35 16) ( 7 - x ) . ( x + 19 ) = 0
6) ( -5 ) + x = 15 17) -5 < x < 1
7) 2 . x - ( -17 ) = 15 18) | x | < 3
8) | x - 2 | = 3 19) ( x - 3 ) . ( x - 5 ) < 0
9) | x - 3 | - 7 = 13 20) 2 . x2 - 3 = 29
10) 72 - 3 . | x + 1 | = 9 21) -6 . x - ( -7) = 25
11) 17 - ( 43 - | x | ) = 45 22) 46 =- ( x - 11 ) = -48
1) x - 2 = -6
x = -6 + 2
x = -4
2) -5 . x - ( -3 ) =13
-5 . x = 13 + ( -3 )
-5 . x = 10
x = 10 : ( -5 )
x = -2
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21. Tìm x ∈ Z biết:
a) x. ( x + 3) = 0
b) (x-2)(5-x)=0
c) (x+1)(x2+1)=0
a)Ta có:
\(x\left(x+3\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x+3=0\Rightarrow x=-3\end{matrix}\right.\)
Vậy \(\left[{}\begin{matrix}x=0\\x=-3\end{matrix}\right.\)
b)Ta có:
\(\left(x-2\right)\left(5-x\right)=0\Rightarrow\left[{}\begin{matrix}x-2=0\\5-x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\)
c)Ta có:
\(\left(x+1\right)\left(x^2+1\right)=0\Rightarrow\left[{}\begin{matrix}x+1=0\\x^2+1=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-1\\\varnothing\end{matrix}\right.\)
Vậy \(x=-1\)
1(X+3)^2-(x-5)(x+5)=-21
2(2x-1)^2-(5-3x)^2=0