Tim x biet
| 2x-1 | - | x-3 | = 0
tim x biet (x+1)*(2x-1)*(4x+3) lon hon 0
Tim x, biet:
(2x-1)2-(2x+3).(2x-3)=0
(2x-1)2-(2x+3).(2x-3)=0
<=>4x2-4x+1-(4x2-9)=0
<=>4x2-4x+1-4x2-9=0
<=>-4x-8=0
<=>-4x=8
<=>x=-2
Tim xthuoc Z biet:
1,|2x-5|-|2x+9|=0
2,|x+1|-|x+2|-|3-x|=7
3,|2x+3|+|3x+2|-|4-x|=10
tim x biet
a. (x-3)(x+5)=0
b./9-2x/+x+3=2x+15
c./x+1/+/x-1/=4
a/ (x - 3)(x + 5) = 0
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+5=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=-5\end{cases}}\)
b/ |9 - 2x| + x + 3 = 2x + 15
=> |9 - 2x| = 2x + 15 - 3 - x
=> |9 - 2x| = x + 12
\(\Rightarrow\orbr{\begin{cases}9-2x=x+12\\9-2x=-x-12\end{cases}}\Rightarrow\orbr{\begin{cases}-2x-x=12-9\\-2x+x=-12-9\end{cases}}\Rightarrow\orbr{\begin{cases}-3x=3\\-x=-21\end{cases}}\Rightarrow\orbr{\begin{cases}x=-1\\x=21\end{cases}}\)
c/ TH1: Nếu x > 1 thì x + 1 + x - 1 = 4
=> 2x = 4
=> x = 2
TH2: Nếu x < 1 thì x + 1 + x - 1 = -4
=> 2x = -4
=> x = -2
TH3: Nếu x = 1 thì 1 + 1 + 1 - 1 = 4 (vô lí)
Vậy x = 2 hoặc x = -2
Câu c thì mình không chắc cho lắm, không biết có đúng không nữa. ._.
tim x biet :
( 2-x ) x (4/5-x ) < 0
(x - 3/2) x ( 2x + 1 ) > 0
tim x biet
/x-\(\frac{3}{5}\)/+2x-1=0
\(\left|x-\frac{3}{5}\right|+2x-1=0\)
\(\Leftrightarrow2x-1=-\left|x-\frac{3}{5}\right|\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=-x-\frac{3}{5}\\2x-1=-\left(-x\right)-\frac{3}{5}\end{cases}\Leftrightarrow\orbr{\begin{cases}2x+x=\frac{-3}{5}+1\\2x-x=\frac{-3}{5}+1\end{cases}}\Leftrightarrow\orbr{\begin{cases}3x=\frac{2}{5}\\x=\frac{2}{5}\end{cases}}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{2}{15}\\x=\frac{2}{5}\end{cases}}\)
Vậy ..................
Chắc cách làm như thế :V
Tim m de pt \(x^2-2x-2\left|x-m\right|+1=0\) co 3 nghiem phan biet
tim x biet (2x+1)+(2x+2)+...+(2x+2015)=0
Có 2015 số hạng
Tổng là (2x+1+2x+2015).2015:2=0
4x+2016=0
4x=-2016
x=-504
Ủng hộ mk nha
( 2x + 1 ) + ( 2x + 2 ) + ... + ( 2x + 2015 ) = 0
=> ( 2x + 2x + .. + 2x ) + ( 1 + 2 + ... + 2015 ) = 0
2015 số 2x
=> 2x . 2015 + 2031120 = 0
=> 2x . 2015 = 0 - 2031120
=> 2x . 2015 = - 2031120
=> 2x = ( - 2031120 ) : 2015
=> 2x = - 1008
=> x = ( - 1008 ) : 2
=> x = - 504
=> ( 2x + 2x + .... + 2x + 2x ) + ( 1 + 2 + 3 + .... + 2015 ) = 0
=> ( 2x.2015 ) + { [ 2015.( 2015 + 1 ] : 2 } = 0
=> 4030x + [ ( 2015 . 2016 ) : 2 ] = 0
=> 4030x + ( 4062240 : 2 ) = 0
=> 4030x + 2031120 = 0
=> 4030x = - 2031120
=> x = - 2031120 : 4030 = - 504
Vậy x = - 504