A) 14-x-10=(-9)+15
B) IxI=5+7=10
C) IxI=(-12)+(-15)+8
D) Ix+5I=4-(-3)+5
E) IxI<4
Giúp mik với
Tìm Max và Min của các biểu thức sau:
A=IxI+7
B=Ix-2I+Iy-5I
C=2Ix-5I-7
D=-IxI+2
E=-Ix+3I-IyI+5
A = |x| + 7
|x| >/ 0
=> A >/ 7
Vậy GTNN của A = 7 kh |x| = 0 <=> x= 0
Bài 1 Tính:
a) 75-5.(15-10)-(-60)
b) 136-(-7)+6-23-36
c) (-15-17).(-15+7)
d) (-9-18):(-9)
Bìa 2 Tìm x:
a) 2x-17=(-3x-18)
b) (13-IxI) +15=20
c) Ix+5I-(x+5)=0
a, 75 - 5 . ( 15 - 10 ) - ( -60 ) = 75 - 5 . 5 + 60 = 135 - 25 = 110
b, 136 - ( -7 ) + 6 - 23 - 36 = 136 + 7 + 6 - 23 - 36 = ( 136 - 36 ) + ( 7 + 6 - 23 ) = 100 - 10 = 90
c, ( -15 - 17 ) . ( -15 + 7 ) = -32 . ( -8 ) = 256
d, ( -9 - 18 ) : ( -9 ) = -27 : ( -9 ) = 3
Bài 2:
a, 2x - 17 = ( -3x - 18 )
<=> 2x + 3x = 17 - 18
<=> 5x = -1
<=> x = -1/5
b, ( 13 - IxI ) + 15 = 20
<=> 13 - |x| = 5
<=> |x| = 8
<=> x = 8 hoặc x = -8
c, Ix + 5I - ( x + 5 ) = 0
<=> |x + 5| = x + 5
Đk: x + 5 ≥ 0 => x ≥ -5
\(\Leftrightarrow\orbr{\begin{cases}x+5=x+5\\x+5=-x-5\end{cases}\Leftrightarrow}\orbr{\begin{cases}0x=0\\2x=-10\end{cases}\Leftrightarrow}\orbr{\begin{cases}x\ge-5\\x=-5\end{cases}}\)
Vậy x ≥ -5
tìm số nguyên x, biết
a, IxI+Ix-10I=20
b,Ix-5I-3=x+2
c,Ix-4I-Ix+10I=30
d,Ix-5I<7
e,Ix-3I=Ix2-3xI
9-25=(7-x)-(25+7)
-6x=18
35-3.IxI =5.(2 mũ 3-4)
10+2.IxI=2.(3 mũ 2-1)
Tìm x biết:
a. IxI + Ix+2I = 3
b. [ 12/25 . ( 0,75 + 7/4) - 1 ] x = [ 7/5 - 3/25 . ( 10,6 - 3/5 ) ]
Giúp mk vs!
\(a)\) \(\left|x\right|=\left|x+2\right|=3\)
\(\text{Trường hợp 1:}\)
\(\Leftrightarrow x+x+2=3\)
\(\Leftrightarrow2x=1\)
\(\Leftrightarrow x=\frac{1}{2}\)
\(\text{Trường hợp 2:}\)
\(\Leftrightarrow-x-x-2=3\)
\(\Leftrightarrow-2x=5\)
\(\Leftrightarrow x=-\frac{5}{2}\)
\(b)\) \([\frac{12}{25}.\left(0,75+\frac{7}{4}\right)-1].x=[\frac{7}{5}-\frac{3}{25}.\left(10,6-\frac{3}{5}\right)]\)
\(\Leftrightarrow[\frac{12}{25}.2,5-1].x=[\frac{7}{5}-\frac{3}{25}.10]\)
\(\Leftrightarrow[1,2-1].x=[\frac{7}{5}-2]\)
\(\Leftrightarrow0,2.x=-\frac{3}{5}\)
\(\Leftrightarrow x=-\frac{3}{5}:0,2\)
\(\Leftrightarrow x-3\)
Tim cac so nguyen x sao cho:
a)Ix+2I+Iy+5I=0
b)IIyI+Ix+2II+IxI=0
a) \(\left|x+2\right|+\left|y+5\right|=0\)
\(\Rightarrow\begin{cases}\left|x+2\right|=0\\\left|y+5\right|=0\end{cases}\)
\(\Rightarrow\begin{cases}x+2=0\\y+5=0\end{cases}\)
\(\Rightarrow\begin{cases}x=-2\\y=-5\end{cases}\)
b) \(\left|\left|y\right|+\left|x+2\right|\right|+\left|x\right|=0\)
\(\Rightarrow\begin{cases}\left|\left|y\right|+\left|x+2\right|\right|=0\\\left|x\right|=0\end{cases}\)
\(\Rightarrow\begin{cases}\left|y\right|+\left|x+2\right|=0\\x=0\end{cases}\)
Thay x = 0 vào biểu thức \(\left|y\right|+\left|x+2\right|=0\), ta đc:
\(\left|y\right|+\left|0+2\right|=0\Rightarrow\left|y\right|+2=0\Rightarrow\left|y\right|=-2\Rightarrow y=\phi\)
Vậy \(x=0;y=\phi\)
9.x + 1=73
2.x - 5 = -17 - 12
10 - x - 5 = - 5 - 7 -11
(-9) . x + 3 = (-2) . (-7) +16
(-12) . x - 34 =2
(-11).x + 9 =130
(-5) .x + 5 = (-15) .(-4) -12
IxI -3=0
(7 - IxI).(2.x - 4) =0
280-(x-140):35 =270
(1900 - 2.x ) : 35- 32 =16
720 :[41-(2x -5 )] =23 .5
(x - 5).(x2 - 4 ) =0
GIÚP MIK VS ,MIK CẦN GẤP
a)9.x + 1=73
9x=73-1
9x=72
x=72:9
x=8
b)2.x - 5 = -17 - 12
2x-5=-29
2x=-29+5
2x=-24
x=-24:2
x=-12
c)10 - x - 5 = - 5 - 7 -11
10-x-5=-12-11
10-x-5=-23
10-x=-23+5
10-x=18
x=10-18
x=-8
d)(-9) . x + 3 = (-2) . (-7) +16
-9x+3=14+16
-9x+3=30
-9x=30-3
-9x=27
x=27:(-9)
x=-3
(-12) . x - 34 =2
-12x=2+34
-12x=36
x=36:(-12)
x=-3
(-11).x + 9 =130
-11x=130-9
-11x=121
x=121:(-11)
x=11
(-5) .x + 5 = (-15) .(-4) -12
-5x+5=60-12
-5x+5=48
-5x=48-5
-5x=43
x=43:(-5)
x=-8,6
IxI -3=0
|x|=3
=>x=+3
(7 - IxI).(2.x - 4) =0
*7-|x|=0 * 2x-4=0
|x|=7 2x=4
=>x=+7 x=4:2
x=2
280-(x-140):35 =270
(x-140):35=280-270
(x-140):35=10
x-140=10.35
x-140=350
x=350+140
x=490
(1900 - 2.x ) : 35- 32 =16
1900-2x=(16+32).35
1900-2x=1680
2x=1900-1680
2x=220
x=220:2
x=110
720 :[41-(2x -5 )] =23 .5
720:[41-(2x-5)]=40
41-(2x-5)=720:40
41-(2x-5)=18
2x-5=41-18
2x-5=23
2x=23+5
2x=28
x=28:2
x=14
(x - 5).(x2 - 4 ) =0
* x-5=0 * x2-4=0
x=0+5 x2=4
x=5 x2=22
=> x=+2
tìm x thuộc Z:
x+Ix-1I
IxI>x
x+5=IxI
Tìm x thuộc z biết
a)2+3x= -15-19
b) 7-IxI .(2x-4)=0
c) Ix+1I -3=0
\(2+3x=-15-19\)
\(\Rightarrow3x=-15-19-2\)
\(\Rightarrow3.x=-36\)
\(\Rightarrow x=-13\)
\(7-\left|x\right|\left(2x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}7-\left|x\right|=0\\2x-4=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}\left|x\right|=7\\2x=4\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\pm7\\x=2\end{cases}}\)
\(\left|x+1\right|-3=0\)
\(\Rightarrow\left|x+1\right|=3\)
\(\Leftrightarrow\orbr{\begin{cases}x+1=3\\x+1=-3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-4\end{cases}}\)
c;
/x+1/ -3 =0
/x+1/ = 0+ 3
/x+1/ = 3
ta chia làm 2TH
TH1 x+1 = 3
x = 3-1
x = 2
TH2 x+1=-3
x = -3 -1
x = -4
vậy \(x\in\left\{2;-4\right\}\)