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Tìm x € Z
A. 17 - 3 | 2 - x | = 4
B. 25 - 7 | 2x - 1| = 18
C. |X4 + 1 | = 5x - (2 - x4)
Trình bày luôn ạ
\(\left(x+2\right)-2=0\)
\(\Rightarrow x+2-2=0\)
\(\Rightarrow x=0\)
\(\left(x+3\right)+1=7\)
\(\Rightarrow x+3+1=7\)
\(\Rightarrow x+4=7\)
\(\Rightarrow x=3\)
\(\left(3x-4\right)+4=12\)
\(\Rightarrow3x-4+4=12\)
\(\Rightarrow3x=12\)
\(\Rightarrow x=4\)
\(\left(5x+4\right)-1=13\)
\(\Rightarrow5x+4-1=13\)
\(\Rightarrow5x+3=13\)
\(\Rightarrow5x=10\)
\(\Rightarrow x=2\)
\(\left(4x-8\right)-3=5\)
\(\Rightarrow4x-8-3=5\)
\(\Rightarrow4x-11=5\)
\(\Rightarrow4x=16\)
\(\Rightarrow x=4\)
\(8-\left(2x+4\right)=2\)
\(\Rightarrow8-2x-4=2\)
\(\Rightarrow4-2x=2\)
\(\Rightarrow2x=2\)
\(\Rightarrow x=1\)
\(7+\left(5x+2\right)=14\)
\(\Rightarrow7+5x+2=14\)
\(\Rightarrow9+5x=14\)
\(\Rightarrow5x=5\)
\(\Rightarrow x=1\)
\(5-\left(3x-11\right)=1\)
\(\Rightarrow5-3x+11=1\)
\(\Rightarrow16-3x=1\)
\(\Rightarrow3x=15\)
\(\Rightarrow x=5\)
A. 5(x-11) + 4(x-3) =10
<=>5x -55 + 4x -12 =10
<=>9x -67 =10
<=>9x =10+67 =77
<=>x =77 : 9 =77/9
B.21 - 5 ( x-7) = 2-3(x-5)
<=>21-5x+35 = 2 - 3x +15
<=>-5x + 56 = -3x + 17
<=>-5x +3x=17-56=-39
<=> -2x =-39
<=> x = -39 : -2 =39/2
C.3(2x-1)-7(x+4)=8-9x
<=>6x -4 -7x-28=-9x+8
<=>-x + 9x = 8+4+28=40
<=> 8x = 40
<=> x = 40:8=5
D. l 4-x l =11
<=>\(\orbr{\begin{cases}4-x=11\\4-x=-11\end{cases}}\)<=> \(\orbr{\begin{cases}x=-7\\x=15\end{cases}}\)
E. 5-3 l x+2 l = -28
<=> 3 l x+2 L = -28 -5 =-33
<=> l x+2 l = -33 :3 =11
<=>\(\orbr{\begin{cases}x+2=11\\x+2=-11\end{cases}}\)<=> \(\orbr{\begin{cases}x=9\\-13\end{cases}}\)
T I C K mk nhé!!!^_^
a ) Ta có : 31 (x + 3) > 0
=> x + 3 > 0
=> x > 3
d)Để (x - 3)(x - 2) < 0 thì có 2 trường hợp
Th1 : \(\Leftrightarrow\hept{\begin{cases}x-3< 0\\x-2>0\end{cases}\Rightarrow\hept{\begin{cases}x< 3\\x>2\end{cases}\Rightarrow2< x< 3}}\)
Th2 : \(\Leftrightarrow\hept{\begin{cases}x-3>0\\x-2< 0\end{cases}\Rightarrow\hept{\begin{cases}x>3\\x< 2\end{cases}\left(loại\right)}}\)
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 |
15 - 2 | 4 + 5x | = 59 <=> 2 | 4 + 5x | = -44 <=> | 4 + 5x | = -22
Vì \(\left|4+5x\right|\ge0\) nên không có x thỏa mãn | 4 + 5x | = -22
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TH1: \(x\le\frac{1}{5}\)=>3-x+1-5x=7=>4-6x=7=>-3=6x=>x=-1/2(nhận)
TH2:\(\frac{1}{5}< x\le3\)=>3-x+5x-1=7=>2+4x=7=>4x=5=>x=5/4(nhận)
TH3:x>3=>x-3+5x-1=7=>6x-4=7=>6x=11=>x=11/6(loại)
Vậy x=-1/2 hoặc x=5/4