0,25 - | 1,5 - x | = 0
| x - 7 | = 1 và 1/2
tìm x
Bài 1: Tìm x biết
1) |5x - 3| = |7 - x|
2) 2 |3 x - 1| - 3x = 7
3) |2x + 3| + 4 = -2x
4) |x + 3/4| - 1/3 = 0
5) 1,6 - |x + 1,5| = 0
6) |x - 1,5| + |2,5 - x| = 0
1) \(|5x-3|=|7-x|\)
\(\Leftrightarrow\orbr{\begin{cases}5x-3=7-x\\5x-3=x-7\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}6x=10\\4x=-4\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{5}{3}\\x=-1\end{cases}}\)
Vậy...
2) \(2.|3x-1|-3x=7\)
\(\Leftrightarrow2.|3x-1|=7+3x\)
\(\Leftrightarrow\orbr{\begin{cases}2.\left(3x-1\right)=7+3x\\2.\left(3x-1\right)=-7-3x\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}6x-2=7+3x\\6x-2=-7-3x\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=9\\9x=-5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=\frac{-5}{9}\end{cases}}\)
Vậy...
5) \(\text{1,6 - |x + 1,5| = 0}\)
\(|x + 1,5| = 1,6-0\)
\(\text{|x + 1,5| = 1,6}\)
\( |x | = 1,6-1,5\)
\(|x|=0,1\)
1/M=(\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+1,5}{1\frac{1}{6}-0,875+0,7}\)) :\(\frac{2012}{2013}\)
2/ Tìm x, biết:\(|x^2+|x-1||=x^2+2|\)
Câu 2 đây:
\(|x^2+|x-1||=x^2+2\)
\(\Rightarrow\orbr{\begin{cases}x^2+\left|x-1\right|=x^2+2\\x^2+\left|x-1\right|=-x^2-2\left(l\right)\end{cases}}\)
\(\Rightarrow\left|x-1\right|=2\Leftrightarrow\orbr{\begin{cases}x=3\\x=-1\end{cases}}\)
a) \(M=\left(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+0,5}{1\frac{1}{6}-0,875+0,7}\right):\frac{2012}{2013}\)
\(=\left(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{2}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\right):\frac{2012}{2013}\)
\(=\left(\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{2\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\right):\frac{2012}{2013}\)
\(=\left(\frac{2}{7}-\frac{2}{7}\right):\frac{2012}{2013}\)
\(=0\)
Tìm x biết:
a. 5.x.(x-1/3)=0
b. (x+1/4).(x-3/7)=0
c. 1,5.x - 2 1/3.x=1,5 - 2/3
chú ý; 2 1/3 có nghĩa là 2 và 1 phần 3(hỗn số)
giai đầy đủ thì bạn tick cho nghen đccộng điểm đó
tìm x biết
0,25 - / 1,5 - x / = 0
... \(\Leftrightarrow\left|1,5-x\right|=0,25\Leftrightarrow\hept{\begin{cases}1,5-x=0,25\\1,5-x=-0,25\end{cases}\Leftrightarrow\hept{\begin{cases}x=1,5-0,25=1,25\\x=1,5+0,25=1,75\end{cases}}}\)Vậy........
/1.5-x=0,25-0
/1.5-x/=0,25
tường hợp 1
1.5-x=0,25
x=1,5-0,25=1,25
trường hợp 2
1,5-x=-0.25
x=1,5-(-0.25)=1,75
Tìm x:
a)7.(x-1)+2x.(1-x)=0
b)0,25-|3,5-x|=0
c)|x+\(\frac{3}{4}\)| -\(\frac{1}{2}\)=0
a, \(7\left(x-1\right)+2x\left(1-x\right)=0\)
\(\Rightarrow\left(7-2x\right)\left(x-1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}7-2x=0\\x-1=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=1\end{cases}}\)
b, \(0,25-\left|3,5-x\right|=0\)
\(\Rightarrow\left|3,5-x\right|=2,5\)
\(\Rightarrow\orbr{\begin{cases}3,5-x=2,5\\3,5-x=-2,5\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=6\end{cases}}\)
c, \(\left|x+\frac{3}{4}\right|-\frac{1}{2}=0\)
\(\Rightarrow\left|x+\frac{3}{4}\right|=\frac{1}{2}\)
\(\Rightarrow\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=\frac{-1}{2}\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{4}\\x=\frac{-5}{4}\end{cases}}\)
a) 7.(x-1) + 2x.(1-x) = 0
7.(x-1) - 2x.(x-1) = 0
(x-1).(7-2x) = 0
=> (x-1) = 0 => x = 1
7-2x = 0 => 2x = 7 => x = 7/2
KL:...
b) 0,25 - | 3,5-x| = 0
=> |3,5 - x| = 0,25
TH1: 3,5 - x = 0,25
x = 3,25
TH2: 3,5 - x = -0,25
x = 3,75
phần c bn dựa vào phần b mak lm nha
a) 7.(x - 1) + 2x.(1 - x) = 0
<=> -2x2 + 9x - 7 = 0
<=> \(\orbr{\begin{cases}x=1\\x=\frac{7}{2}\end{cases}}\)
=> \(\orbr{\begin{cases}x=1\\x=\frac{7}{2}\end{cases}}\)
b) 0,25 - |3,5 - x| = 0
<=> - |3,5 - x| = 0 - 0,25
<=> - |3,5 - x| = -0,25
<=> |3,5 - x| = 0,25
Ta xét 2 th:
Th1: |x| = 3,5 - 0,25
<=> |x| = \(\frac{13}{4}\)
Th2: |x| = 3,5 + 0,25
<=> x = \(\frac{15}{4}\)
=> \(\orbr{\begin{cases}x=\frac{13}{4}\\\frac{15}{4}\end{cases}}\)
c) \(\left|x+\frac{3}{4}\right|-\frac{1}{2}=0\)
<=> \(\left|x+\frac{3}{4}\right|=0+\frac{1}{2}\)
<=> \(\left|x+\frac{3}{4}\right|=\frac{1}{2}\)
Ta xét 2 th:
Th1: \(x+\frac{3}{4}=\frac{1}{2}\)
<=> \(x=\frac{1}{2}-\frac{5}{4}\)
<=> \(x=-\frac{3}{4}\)
Th2: \(x+\frac{3}{4}=\frac{1}{2}\)
<=> \(x=\frac{1}{2}-\frac{3}{4}\)
<=> \(x=-\frac{1}{4}\)
=> \(\orbr{\begin{cases}x=-\frac{3}{4}\\x=-\frac{1}{4}\end{cases}}\)
Tìm x, biết:
a) 2-x = 2 ( x - 2 ) 3 ; b) 8 x 3 - 72x = 0;
c) ( x - 1 , 5 ) 6 + 2 ( 1 , 5 - x ) 2 = 0; d) 2 x 3 +3 x 2 +3 + 2x = 0;
e) x 3 - 4x- 14x(x - 2) = 0; g) x 2 (x + 1)- x(x + 1) + x(x - 1) = 0.
Tìm x
a,(x . 0,25 + 1999) . 2000=(53 + 1999)-2000
b,(5457 + x : 2) : 7 = 1075
c,1 - (12/5 + x - 8/9) : 16/9 = 0
Giúp mình với nhé
Lời giải:
a. $(x.0,25+1999).2000=(53+1999).2000$
$x.0,25.2000+1999.2000=53.2000+1999.2000$
$x.0,25.2000=53.2000$
$x.0,25=53$
$x=53:0,25=212$
b.
$(5457+x:2):7=1075$
$5457+x:2=1075\times 7=7525$
$x:2=7525-5457=2068$
$x=2068\times 2=4136$
c.
$1-(\frac{12}{5}+x-\frac{8}{9}): \frac{16}{9}=0$
$(\frac{12}{5}+x-\frac{8}{9}):\frac{16}{9}=1$
$\frac{12}{5}+x-\frac{8}{9}=1.\frac{16}{9}=\frac{16}{9}$
$\frac{68}{45}+x=\frac{16}{9}$
$x=\frac{16}{9}-\frac{68}{45}=\frac{4}{15}$
2. Tìm x:
a) 4/5 + x = 2/3
b) 1/2 - x = 7/12
c) 3 và 1/2 : x = -7/2
d) 3/8 - 1/6 x =5/2
e) x + 50%x = -1,5
a: x=2/3-4/5=10/15-12/15=-2/15
b: 1/2-x=7/12
=>x=1/2-7/12=-1/12
c: =>7/2:x=-7/2
=>x=-1
d: =>1/6x=3/8-5/2=3/8-20/8=-17/8
=>x=-17/8*6=-102/8=-51/4
e: =>1,5x=-1,5
=>x=-1
Tìm x biết :(2x/3-3):(-10)=2/5 ; 1,5 x -2 1/3 x = 1,5-2/3 ; (x+1/4) (x-3/7)=0
GGiúp mình với, mai đi học rồi =(((