Tim x thuoc Z biet :
a . | 2x - 5 | = 13
b. | 7x + 3 | = 66
c. | 5x - 2 | < hoac bang 13
Giup to voi
4. Tìm x
Z biết:
a) | 2x – 5 | = 13
b) 7x + 3| = 66
c) | 5x – 2| 0
`a)|2x-15|=13`
`**2x-15=13`
`<=>2x=28`
`<=>x=14.`
`**2x-15=-13`
`<=>2x=-2`
`<=>x=-1.`
`b)|7x+3|=66`
`**7x+3=66`
`<=>7x=63`
`<=>x9`
`**7x+3=-66`
`<=>7x=-69`
`<=>x=-69/7`
`c)|5x-2|=0`
`<=>5x-2=0`
`<=>5x=2`
`<=>x=2/5`
\(a,\Leftrightarrow\left[{}\begin{matrix}2x-5=13\\2x-5=-13\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=9\\x=-4\end{matrix}\right.\)
Vậy ...
\(b,\Leftrightarrow\left[{}\begin{matrix}7x+3=66\\7x+3=-66\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=9\\x=-\dfrac{69}{7}\end{matrix}\right.\)
Vậy ...
\(c,\Leftrightarrow5x-2=0\)
\(\Leftrightarrow x=\dfrac{5}{2}\)
Vậy ...
a \(\Rightarrow\left[{}\begin{matrix}2x-5=13\\2x-5=-13\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}2x=18\\2x=-8\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=9\\x=-4\end{matrix}\right.\)
b \(\Rightarrow\left[{}\begin{matrix}7x+3=66\\7x+3=-66\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}7x=63\\7x=-69\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=9\\x=-\dfrac{69}{7}\end{matrix}\right.\)
c \(\Rightarrow5x-2=0\Rightarrow x=\dfrac{2}{5}\)
tim x,y thuoc Z biet
|y|.|2x+3|=8
|2x+4|+|y-3|=0
|x-1|+|2y+7|=3
|x+5|+|2y+6| nho hon hoac bang 0
Tim x thuoc Z
|5x-2|be hon hoac bang 13
Vì |5x - 2| < hoặc = 13
=> |5x - 2| thuộc {0; 1; 2;....;13}
=> 5x - 2 thuộc {0; -1; 1; -2; 2;...;-13; 13}
Mà 5x - 2 chia 5 dư 3
=> 5x - 2 thuộc {-2; 3; 8; -7; 13}
=> 5x thuộc {0; 5; 10; -5; 15}
=> x thuộc {0; 1; 2; -1; 3}
Để |5x-2| < hơn hoặc = 13
=>x < hơn hoặc = 3
=>x\(\varepsilon\){1;-1;3;-3}
TH1: 5x-2 = 13
=> 5x = 13+2 = 15
=> x= 15:5 = 3
TH2: 5x-2 = -13
=> 5x = -13+2 = -11
=> x= -11 :5 = -2,2
duyệt đi
tìm x thuoc Z biet
2 < = |2x - 3 | < 4 ( < = la lon hon hoac bang)
cac ban lam nhanh ho minh voi minh can gap 4 gio phai nop roi ai nhanh dung minhf tick cho
Ta có : \(2\le|2x-3|< 4\)
\(\Rightarrow|2x-3|=3\)
\(\Rightarrow2x-3=3\) hoặc \(2x-3=-3\)
\(\Rightarrow2x=6\) hoặc \(2x=0\)
\(\Rightarrow x=3\) hoặc \(x=0\)
Tim x thuoc Z
a.\2x-5\=13
b.\7x+3\=66
c.\5x-2\<=13
a) => 2x-5 = 13
2x-5 = -13
=> 2x = 13+5 = 18
2x = -13+5 = -8
=> x= -18:2 = -9
x= -8:2 = -4
b) 7x+3 = 66
=> 7x+3 = 66
7x+3 = -66
7x = 66-3 = 33
7x = -66 - 3 = -69
=> x= 33:7 = ????
x= -69:7 = ???? sai đề hay sao ý
c) => 5x-2 = 13
=> 5x -2 = -13
5x = 13+2 = 15
5x = -13+2 = -11
=> x= 15:5 = 3
x= -11: 5 = -2,2
duyệt đi
ý câu b) sai chỗ này: 7x = 66-3 = 63
7x = -66 - 3 = -69
=> x= 63:7 = 9
x= -69 :7 = -9,857.........
bài lạ duyệt đi
Tim x, y thuoc Z biet : | x + 45 - 40 | + | y + 10 - 11 | nho hon hoac bang 0
tim x thuoc z , biet : 2x-3/3 + -3x +4/4+5x-12/5 = 241/60
Cho | x | lon hon hoac bang 3 ; | y | = 5 , x; y thuoc tap hop Z . tim x ; y
cho a thuoc z biet :
a cong x bang 5
a - x bang 2
tim a,b thuoc z biet :
a công x bằng b
a trừ x bằng b