Tìm x
a. (x + 1) + (x + 2) + (x + 3) = 24
b. x + x + 8 = 24
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bài 2 tìm x
a,106- ( x+ 7) =9
x+7 = 106 - 9
x+7 = 107
x= 107 - 7
x=100
b, 2 x ( x+ 4) + 5 =65
2 x (x+4) = 65 - 5
2 x (x+4) = 60
x+4 = 60:2
x+4= 30
x= 30 - 4
x=26
c, (16x x -32) x 45=0
16 x X - 32 = 0: 45
16 x X - 32 =0
16 x X = 0 + 32
16 x X = 32
X= 32:16
X=2
d, x+4 x x = 100 : 5
X + 4 x X = 20
(1+4) x X = 20
5 x X = 20
X= 20:5
X=4
a: x=-5/11+2/11=-3/11
b: =>x=-3/24+20/24+1/24=18/24=3/4
c: =>5/8-x=1/9+5/4=4/36+45/36=49/36
=>x=5/8-49/36=-53/72
d: =>2/3-x=1/3
=>x=1/3
e: =>1/5:x=12/35
=>x=7/12
Bài 2:
a: \(\Leftrightarrow x-1\in\left\{1;-1;2;-2;3;-3;6;-6\right\}\)
=>\(x\in\left\{2;0;3;-1;4;-2;7;-5\right\}\)
b: \(\Leftrightarrow x+3\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
=>\(x\in\left\{-2;-4;0;-6;2;-8;12;-18\right\}\)
c: \(\Leftrightarrow x+3\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)
=>\(x\in\left\{-2;-4;-1;-5;0;-6;1;-7;3;-9;9;-15\right\}\)
d: =>x+1+15 chia hết cho x+1
=>\(x+1\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
=>\(x\in\left\{0;-2;2;-4;4;-6;14;-16\right\}\)
` 8/23 . 46/24 =1/3 .x`
`=>8/23 . 23/12 =1/3 . x`
`=> 1/3 . x=2/3`
`=>x=2/3 : 1/3`
`=>x=2/3 . 3`
`=> x= 6/3`
`=>x=2`
`----`
`1/5 : x= 1/5-1/7`
`=>1/5 : x= 7/35 - 5/35`
`=> 1/5 :x= 2/35`
`=>x= 1/5 : 2/35`
`=>x=1/5 . 35/2`
`=>x=7/2`
`----`
`4/9 - (x-1/2)^2 =1/3`
`=> (x-1/2)^2 =4/9-1/3`
`=> (x-1/2)^2 =4/9- 3/9`
`=> (x-1/2)^2 =1/9`
`=> (x-1/2)^2 = (+- 1/3)^2`
`@ TH1`
`x-1/2=1/3`
`=>x=1/3+1/2`
`=>x= 2/6 + 3/6`
``=>x= 5/6`
`@ TH2`
`x-1/2=-1/3`
`=>x=-1/3 +1/2`
`=>x= -2/6 + 3/6`
`=>x=1/6`
`----`
`3,2 . x-(4/5+2/3) : 3 2/3 = 7/10`
`=> 3,2 . x-22/15 : 11/3 = 7/10`
`=> 3,2 . x-22/15 = 7/10 . 11/3`
`=> 3,2 . x-22/15 =77/30`
`=> 3,2 .x= 77/30 + 22/15`
`=> 3,2 .x=121/30`
`=>x= 121/30. 5/16`
`=>x= 121/96`
Câu b,
= 50x + (1 + 3 + 5 + ..... + 99) = 2550
= 50x + 2500 = 2550
= 50x = 2550 - 2500
= 50x = 50
= x = 50 : 50
= x = 1
a) 6/-x=x/-24
=> -x.x=6.-24
=>-x.x=-144
=>x=12 hay x=-12
b)9/x=-35/105
=>9/x=-1/3
=>x=9.3/-1=-27
=>x=-27
c)x-1/8=5/8
=>x=5/8+1/8
=>x=3/4
d)x-1/2-(3/2+x)=-2
=>-x+4/2=-2
=>-x/2=0
=>x=0
e)x+1/3=-12/5.10/6
x+1/3=-4
x=-4-1/3
x= -13/3
#YM
a: 3(x+7)-2x+5>0
=>3x+21-2x+5>0
=>x+26>0
=>x>-26
Sửa đề: \(\dfrac{x+2}{18}-\dfrac{x+3}{8}< \dfrac{x-1}{9}-\dfrac{x-4}{24}\)
=>\(\dfrac{4\left(x+2\right)}{72}-\dfrac{9\left(x+3\right)}{72}< \dfrac{8\left(x-1\right)}{72}< \dfrac{3\left(x-4\right)}{72}\)
=>\(4\left(x+2\right)-9\left(x+3\right)< 8\left(x-1\right)-3\left(x-4\right)\)
=>\(4x+8-9x-27< 8x-8-3x+12\)
=>-5x-19<5x+4
=>-10x<23
=>\(x>-\dfrac{23}{10}\)
b: \(3x+2+\left|x+5\right|=0\left(1\right)\)
TH1: x>=-5
(1) trở thành: 3x+2+x+5=0
=>4x+7=0
=>\(x=-\dfrac{7}{4}\left(nhận\right)\)
TH2: x<-5
=>x+5<0
=>|x+5|=-x-5
Phương trình (1) sẽ trở thành:
\(3x+2-x-5=0\)
=>2x-3=0
=>2x=3
=>\(x=\dfrac{3}{2}\)
a) Ta có: \(\left|4-5x\right|=24\)
\(\Leftrightarrow\left[{}\begin{matrix}-5x+4=24\\-5x+4=-24\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-5x=20\\-5x=-28\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=\dfrac{28}{5}\end{matrix}\right.\)
Vậy: \(x\in\left\{-4;\dfrac{28}{5}\right\}\)
b) Ta có: \(\left(8+x\right)\left(6-x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+8=0\\6-x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-8\\x=6\end{matrix}\right.\)
Vậy: \(x\in\left\{-8;6\right\}\)
a) \(\left|4-5x\right|=24\)
\(\Leftrightarrow\left[{}\begin{matrix}4-5x=24\\4-5x=-24\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=\dfrac{28}{5}\end{matrix}\right.\)
b) \(\left(8+x\right)\left(6-x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}8+x=0\\6-x=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-8\\x=6\end{matrix}\right.\)
a: \(\dfrac{-8}{3}\cdot\dfrac{15}{24}=\dfrac{-8}{24}\cdot\dfrac{15}{3}=\dfrac{-1}{3}\cdot5=-\dfrac{5}{3}\)
b: \(=\dfrac{3}{4}\cdot\dfrac{1}{-9}=\dfrac{-1}{12}\)
c: \(x=-\dfrac{7}{6}+\dfrac{5}{8}=-\dfrac{13}{24}\)
d: \(x=-\dfrac{14}{25}-\dfrac{3}{4}=\dfrac{-56-75}{100}=\dfrac{-131}{100}\)
a ) (x+1)+(x+2)+(x+3)=24
=>x+1+x+2+x+3=24
=>(x+x+x)+(1+2+3)=24
=>3x+6=24
=>3x = 24-6
=> 3x = 18
=> x = 18 : 3
=> x = 3
b )x+x+8 =24
=>2x = 24-8
=> 2x = 16
=> x = 16 : 2
=> x =8
k cho mh nha
.
a. ( x+1 )+(x+2)+(x+3)=24
x+1+x+2+x+3=24
x+x+x+1+2+3=24
3*x+(1+2+3)=24
3*x+6=24
3*x=24-6
3*x=18
x=18:3
x=6
b.x+x+8=24
2*x+8=24
2*x=24-8
2*x=16
x=16:2
x=8
Lần sau mấy bài dễ thế này em nên tư duy một tí nha!