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I
21 tháng 2 2020
(x+7)(x-9)=0
=>\(\orbr{\begin{cases}x+7=0\\x-9=0\end{cases}}\)
=>\(\orbr{\begin{cases}x=-7\\x=9\end{cases}}\)
|2x-5| -7 =22
=> |2x-5|=29
=>\(\orbr{\begin{cases}2x-5=29\\2x-5=-29\end{cases}}\)
=>\(\orbr{\begin{cases}2x=34\\2x=-24\end{cases}}\)
=>\(\orbr{\begin{cases}x=17\\x=-12\end{cases}}\)
(x-2)(5-x)=0
=>\(\orbr{\begin{cases}x-2=0\\5-x=0\end{cases}}\)
=>\(\orbr{\begin{cases}x=2\\x=5\end{cases}}\)
21 tháng 2 2020
\(\left(x+7\right)\left(x-9\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+7=0\\x-9=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-7\\x=9\end{cases}}}\)
N
16 tháng 7 2019
a) \(\frac{22}{7}:\left(11-x\right)+\frac{2}{3}=\frac{7}{5}\)
\(\frac{22}{7}:\left(11-x\right)=\frac{7}{5}-\frac{2}{3}\)
\(\frac{22}{7}:\left(11-x\right)=\frac{11}{15}\)
\(11-x=\frac{22}{7}:\frac{11}{15}\)
\(11-x=\frac{30}{7}\)
\(x=11-\frac{30}{7}\)
\(x=\frac{47}{7}\)
b) \(22.\left(x+1\right)-12,5=53,5\)
\(22.\left(x+1\right)=53,5+12,5\)
\(22.\left(x+1\right)=66\)
\(x+1=66:22\)
\(x+1=3\)
\(x=3-1\)
\(x=2\)
c) \(\left(x-\frac{1}{2}\right).\frac{5}{2}+\frac{1}{2}=\frac{7}{4}\)
\(\left(x-\frac{1}{2}\right).\frac{5}{2}=\frac{7}{4}-\frac{1}{2}\)
\(\left(x-\frac{1}{2}\right).\frac{5}{2}=\frac{5}{4}\)
\(x-\frac{1}{2}=\frac{5}{4}:\frac{5}{2}\)
\(x-\frac{1}{2}=\frac{1}{2}\)
\(x=\frac{1}{2}+\frac{1}{2}\)
\(x=1\)
17 tháng 7 2019
a)22/7:(11-x)=7/5-2/3
22/7:(11-x)=11/15
11-x=22/7:11/15
11-x=30/7
x=11-30/7
x=47/7
vậy x=47/7
b)22.(x+1)=53,5+12,5
22.(x+1)=66
x+1=66:2
x+1=3
x=3-1
x=2
vậy x=2
c)(x-1/2).5/2=7/4-1/2
(x-1/2).5/2=5/4
x-1/2=5/4:5/2
x-1/2=1/2
x=1/2+1/2
x=1
vậy x=1
bạn hãy tích đúng cho mình nhé
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
11 tháng 5 2024
a; \(\dfrac{93}{17}\): \(x\) + (- \(\dfrac{21}{17}\)) : \(x\) + \(\dfrac{22}{7}\): \(\dfrac{22}{3}\) = \(\dfrac{5}{14}\)
\(\dfrac{94}{17}\) \(\times\) \(\dfrac{1}{x}\) - \(\dfrac{21}{17}\) \(\times\) \(\dfrac{1}{x}\) + \(\dfrac{3}{7}\) = \(\dfrac{5}{14}\)
\(\dfrac{72}{17}\) \(\times\) \(\dfrac{1}{x}\) + \(\dfrac{3}{7}\) = \(\dfrac{5}{14}\)
\(\dfrac{72}{17x}\) = \(\dfrac{5}{14}\) - \(\dfrac{3}{7}\)
\(\dfrac{72}{17x}\) = - \(\dfrac{1}{14}\)
17\(x\) = 72.(-14)
17\(x\) = - 1008
\(x\) = - 1008 : 17
\(x\) = - \(\dfrac{1008}{17}\)
Vậy \(x\) \(=-\dfrac{1008}{17}\)
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
11 tháng 5 2024
b; - \(\dfrac{32}{27}\) - (3\(x\) - \(\dfrac{7}{9}\))3 = - \(\dfrac{24}{27}\)
- \(\dfrac{32}{27}\) + \(\dfrac{24}{27}\) = (3\(x\) - \(\dfrac{7}{9}\))3
(3\(x-\dfrac{7}{9}\))3 = - \(\dfrac{8}{27}\)
(3\(x-\dfrac{7}{9}\))3 = (- \(\dfrac{2}{3}\))3
3\(x-\dfrac{7}{9}\) = - \(\dfrac{2}{3}\)
3\(x\) = - \(\dfrac{2}{3}\) + \(\dfrac{7}{9}\)
3\(x\) = \(\dfrac{1}{9}\)
\(x\) = \(\dfrac{1}{9}\) : 3
\(x\) = \(\dfrac{1}{27}\)
Vậy \(x=\dfrac{1}{27}\)
DA
17 tháng 2 2020
d) |2x – 5| –7 = 22
| 2x -5 | = 22+7
| 2x -5 | = 29
TH1: 2x-5 = -29
2x = -29+5
2x= -24
x= -24:2
x= -12
TH2: 2x -5 =29
2x = 29+5
2x= 34
x= 34:2
x= 17
Vậy...
15 tháng 5 2022
a: \(\left|x\right|-\dfrac{38}{7}\left|x\right|-\dfrac{3}{4}=2\left|x\right|-\dfrac{8}{7}\)
\(\Leftrightarrow\left|x\right|\cdot\dfrac{-45}{7}=-\dfrac{8}{7}+\dfrac{3}{4}=\dfrac{-32+21}{28}=\dfrac{-11}{28}\)
=>|x|=11/180
=>x=11/180 hoặc x=-11/180
b: \(\Leftrightarrow x\cdot\dfrac{13}{4}-\dfrac{7}{6}x=\dfrac{5}{12}+\dfrac{5}{3}\)
=>25/12x=25/12
hay x=1
NJ
11 tháng 2 2018
1.
a, \(x-14=3x+18\)
\(\Rightarrow x-3x=18+14\)
\(\Rightarrow-2x=32\Rightarrow x=\frac{32}{-2}=-16\)
b, \(\left(x+7\right).\left(x-9\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+7=0\\x-9=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-7\\x=9\end{cases}}}\)
c, \(\left|2x-5\right|-7=22\)
\(\Rightarrow\left|2x-5\right|=22+7\)
\(\Rightarrow\left|2x-5\right|=29\)
\(\Rightarrow\orbr{\begin{cases}2x+5=29\\2x-5=29\end{cases}}\Rightarrow\orbr{\begin{cases}2x=24\\2x=34\end{cases}\Rightarrow}\orbr{\begin{cases}x=12\\x=17\end{cases}}\)
d, \(\left(\left|2x\right|-5\right)-7=22\)
\(\Rightarrow\left(\left|2x\right|-5\right)=29\)
\(\Rightarrow\left|2x\right|=29+5\Rightarrow\left|2x\right|=34\Rightarrow x=\pm17\)
e, \(\left|x+3\right|+\left|x+9\right|+\left|x+5\right|=4x\)
Vì \(\left|x+3\right|\ge0;\left|x+9\right|\ge0;\left|x+5\right|\ge0;4x\ge0\)
Nên \(\left|x+3\right|+\left|x+9\right|+\left|x+5\right|=4x\ge0\)
\(\Rightarrow\left|x+3\right|>0\Rightarrow\left|x+3\right|=x+3\)
\(\left|x+9\right|>0\Rightarrow\left|x+9\right|=x+9\)
\(\left|x+5\right|>0\Rightarrow\left|x+5\right|=x+5\)
Ta có :
\(x+3+x+9+x+5=4x\)
\(\Rightarrow3x+\left(3+9+5\right)=4x\)
\(\Rightarrow4x-3x=17\)
\(\Rightarrow x=17\)
2. a , b sai đề bn
c, \(\left(5x+1\right).\left(y-1\right)=4\)
\(\Rightarrow\left(5x+1\right).\left(y-1\right)\inƯ\left(4\right)\)
\(\text{ }Ư\left(4\right)=\left\{1;-1;2;-2;4;-4\right\}\)
Ta có bảng sau :
| 5x+1 | 1 | -1 | 2 | -2 | 4 | -4 |
| y-1 | -4 | 4 | -2 | 2 | -1 | 1 |
| x | 0 | -2/5 | 1/5 | -3/5 | 3/5 | -1 |
| y | -3 | 5 | -1 | 3 | 0 | 2 |
d, \(5xy-5x+y=5\)
\(\Rightarrow\left(5xy-5x\right)+y=5\)
\(\Rightarrow5x.\left(y-1\right)+y=5\)
\(\Rightarrow\left(5x+1\right).\left(y-1\right)=4\)
\(\Rightarrow\left(5x+1\right).\left(y-1\right)\inƯ\left(4\right)\)
\(Ư\left(4\right)=\left\{1;-1;2;-2;4;-4\right\}\)
Ta có bảng sau :
| 5x+1 | 1 | -1 | 2 | -2 | 4 | -4 |
| y-1 | -4 | 4 | -2 | 2 | -1 | 1 |
| x | 0 | -2 | 1/5 | -3/5 | 3/5 | -1 |
| y | -3 | 5 | -1 | 3 | 0 | 2 |
17 tháng 2 2021
a) \(-12\left(x-5\right)+7\left(3-x\right)=5\)
\(\Rightarrow-12x+60+21-7x=5\)
\(\Rightarrow-19x+81=5\)
\(\Rightarrow-19x=-76\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
b) \(30\left(x+2\right)-6\left(x-5\right)-24x=100\)
\(\Rightarrow30x+60-6x+30-24x=100\)
\(\Rightarrow0x+90=100\)
\(\Rightarrow0x=10\)(Vô lí)
Vậy không có x
KK
8 tháng 2 2019
a) x - 14 = 3x + 18
=> x - 3x = 18 + 14
=> -2x = 32
=> x = 32 : (-2)
=> x = -16
b) 2(x - 5) - 3(x - 4) = -6 + 15.(-3)
=> 2x - 10 - 3x + 12 = -6 - 45
=> -x + 2 = -51
=> -x = -51 - 2
=> -x = -53
=> x = 53
KK
8 tháng 2 2019
c) (x + 7)(x - 9) = 0
=> \(\orbr{\begin{cases}x+7=0\\x-9=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=-7\\x=9\end{cases}}\)
Vậy ...
d) |2x - 5| - 7 = 22
=> |2x - 5| = 22 + 7
=> |2x - 5| = 29
=> \(\orbr{\begin{cases}2x-5=29\\2x-5=-29\end{cases}}\)
=> \(\orbr{\begin{cases}2x=34\\2x=-24\end{cases}}\)
=> \(\orbr{\begin{cases}x=17\\x=-12\end{cases}}\)
Vậy ...
7x - 2 + 5x = 22
7x + 5x = 22 + 2
12x = 24
x = 24 : 12
x = 2
=> \(7\cdot x-2+5\cdot x=22\)
=> \(7\cdot x+5\cdot x=22+2\)
=> \(12\cdot x=24\)
=> \(x=24:12\)
=> \(x=2\)
Vậy \(x=2\)