bài 1:Tìm x,biết:
a)2.7.4x=23.7.43
b)Ix-1I=3x+2
c)\(\frac{3}{4}\)-I2x+1I=\(\frac{7}{8}\)
tìm x
a,I2x-1I=x-2
b,I2x+1I=3x
c,I2x+1I=4
d,Ix-3I=1/2
e,Ix+1I+Ix-2I=0
f,I2x-1I+Ix+2I=0
A, bạn ơi mình biết làm hết r
B,cài này dễ lằm bạn nghĩ đi okeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
tìm xa,I2x 1I x 2b,I2x 1I 3xc,I2x 1I 4d,Ix 3I 1 2e,Ix 1I Ix 2I 0f,I2x 1I Ix 2I 0
Tìm x:
a,I Ix-1I-1I=2
b,I I3x-1I-5I=2
c,I I2x-3I-x+1I=42-8
d,I(x+1)Ix-3I=x-3
a) \(\left|\left|x-1\right|-1\right|=2\Rightarrow\orbr{\begin{cases}\left|x-1\right|-1=2\\\left|x-1\right|-1=-2\end{cases}}\Rightarrow\orbr{\begin{cases}\left|x-1\right|=3\\\left|x-1\right|=-1\left(l\right)\end{cases}}\)
TH1: x - 1 = 3
x = 4
TH2: x - 1 = - 3
x = - 2
b) Tương tự câu a.
c) \(\left|\left|2x-3\right|-x+1\right|=42-8\)
\(\left|\left|2x-3\right|-x+1\right|=34\)
TH1: \(\left|2x-3\right|-x+1=34\)
\(\left|2x-3\right|-x=33\)
Với \(x\ge\frac{3}{2}\), ta có \(2x-3-x=33\Rightarrow x=36\) (tm)
Với \(x< \frac{3}{2}\), ta có \(3-2x-x+1=34\Rightarrow-3x=30\Rightarrow x=-10\left(tm\right)\)
TH2: \(\left|2x-3\right|-x+1=-34\)
\(\left|2x-3\right|-x=-35\)
Với \(x\ge\frac{3}{2}\), ta có \(2x-3-x=-35\Rightarrow x=-32\) (l)
Với \(x< \frac{3}{2}\), ta có \(3-2x-x+1=-34\Rightarrow-3x=38\Rightarrow x=\frac{38}{3}\left(l\right)\)
d) Tương tự câu c.
Tìm x
a, 2 Ix-3I-5=3
b, 2 I2x+3I + I2x+3I=6
c, 3 Ix+1I^2 + Ix+1I^2=16
a ) 2|x - 3| - 5 = 3 <=> 2|x - 3| = 8 <=> |x - 3| = 4 => x - 3 = ± 4
TH1 : x - 3 = 4 => x = 7
TH2 : x - 3 = - 4 => x = - 1
Vậy x = { - 1; 7 }
b ) 2|2x + 3| + |2x + 3| = 6 <=> 3|2x + 3| = 6 => |2x + 3| = 2 => 2x + 3 = ± 2
=> x = { - 5/2 ; - 1/2 }
c ) 3|x + 1|2 + |x + 1|2 = 16
4|x + 1|2 = 16
=> |x + 1|2 = 4 = 22 ( ko xét TH |x + 1| = - 2 vì |x + 1| ≥ 0 )
=> |x + 1| = 2 => x + 1 = ± 2 => x = { - 3; 1 }
Tìm x,y
a) Ix-1I + Ix+2I =0
b) I2x-1I + Iy^2-yI = 0
c) Ix+1I + Ix+2I =3
#)Giải :
a) \(\left|x-1\right|+\left|x+2\right|=0\Leftrightarrow\orbr{\begin{cases}x-1=0\\x+2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\\x=-2\end{cases}}}\)
b) \(\left|2x-1\right|+\left|y^2-y\right|=0\Leftrightarrow\orbr{\begin{cases}2x-1=0\\y^2-y=0\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=1\\y^2=y\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{1}{2}\\y\in\left\{-1;0;1\right\}\end{cases}}}\)
tìm x biết
b) 3x - x^3=0
c) (x-1).(x-3)=0
d) Ix+1I + Ix+2I+I2x+3I=2016x
b) ta có: x-1 = 0 => x= 0+1 = 1
x-3 = 0 => x= 0+3 = 3
vậy x =1 và x = 3
b)<=>3x-x3=-x(x2-3)
=>-x(x2-3)=0
Th1:-x=0
Th2:x2-3=0
=>x2=3
=>x=\(\pm\sqrt{3}\)
c)(x-1).(x-3)=0
Th1:x-1=0
=>x=0
Th2:x-3=0
=>x=3
d)Ix+1I + Ix+2I+I2x+3I=2016x
<=>Ix+1I + Ix+2I+I2x+3I=|2x+3|+|x+2|+|x+1|
=>|2x+3|+|x+2|+|x+1|=2016x
=>x\(\approx\)0.00298210735586481
1/ Tìm x, y biết:
a/ x.3 = y.7 và 2x - y = 4
b/ Ix - 1I - \(\frac{1}{2}=\frac{3}{4}\)
c/ I x + 1 I + I y - 2 I = 0
d/ (22 :4) . 2x = 4
2/ Tìm GTNN của:
a/ A = 3. I2x + 1I +5
b/ B = I x - 2014I + I x - 2015I
3/ Cho \(\frac{a}{b}=\frac{c}{d}\) CMR:
\(\frac{2a-3b}{2a+3b}=\frac{2c-3d}{2c+3d}\)
\(c,Đặt\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=k.b\)
\(\Rightarrow c=d.k\)
\(-Tacó:\frac{2a-3b}{2a+3b}=\frac{2k.b-3b}{2k.b+3b}=\frac{b.\left(2k-3\right)}{b\left(2k+3\right)}=\frac{2k-3}{2k+3}\left(1\right)\)
\(-Tacó:\frac{2c-3d}{2c+3d}=\frac{2d.k-3d}{2d.k+3d}=\frac{d.\left(2k-3\right)}{d.\left(2k+3\right)}=\frac{2k-3}{2k+3}\left(2\right)\)
\(Từ\left(1\right),\left(2\right)\Rightarrow\frac{2a-3b}{2a+3b}=\frac{2c-3d}{2c+3d}\)
Bài 1: 2 cạnh của 1 tam giác là 16&24 . hiệu hai đường cao tương ứng là 7. tìm 2 dg cao ấy
Bài 2 : tìm x
a/Ix-1I<1/2
b/I2x+5I>5/2
c/Ix-5I<3và x\(\in\)z
bài 3: \(\frac{a+b+c}{d}=\frac{b+c+d}{a}=\frac{c+d+a}{b}=\frac{a+b+d}{c}=k=?\)
Tìm x,y biết
a,I2x-1I = Ix+3I
b,IxI+I2y-6I=0
c,Ix-2I>3
d,Ix-7I=x-7
e,I2x+6I-2x-6