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a, => |15-x| = 2+3
=> |15-x| = 5
=> 15-x = -5 hoặc 15-x = 5
=> x = 10 hoặc x = 10
Vậy ......
Tk mk nha
a/|15-x|=|-2|+|-3|
=>|15-x|=2+3=5
=>\(15-x=\hept{\begin{cases}5\\-5\end{cases}}\)
=>\(x=\hept{\begin{cases}10\\15\end{cases}}\)
.........
k nha , thanks
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\(\left(x-2\right)\left(x+\frac{2}{3}\right)>0\)
Có 2 trường hợp :
\(\left(1\right)\hept{\begin{cases}x-2>0\\x+\frac{2}{3}>0\end{cases}}\Rightarrow\hept{\begin{cases}x>2\\x< \frac{2}{3}\end{cases}}\) Loại
\(\left(2\right)\hept{\begin{cases}x-2< 0\\x+\frac{2}{3}< 0\end{cases}}\Rightarrow\hept{\begin{cases}x< 2\\x>-\frac{2}{3}\end{cases}}\Rightarrow-\frac{2}{3}< x< 2\)
Mà x thuộc Z
=> x = {0 ; 1}
Vì ( x - 2 ) . ( x + \(\frac{2}{3}\)) > 0
\(\Rightarrow\)x - 2 và x + \(\frac{2}{3}\)phải cùng dấu
Xét 2 trường hợp :
TH1 : \(\hept{\begin{cases}x-2>0\\x+\frac{2}{3}>0\end{cases}}\Rightarrow\hept{\begin{cases}x>2\\x>-\frac{2}{3}\end{cases}\Rightarrow-\frac{2}{3}< 2< x\Rightarrow x\in\left\{3;4;5;6;...\right\}}\)
TH2 : \(\hept{\begin{cases}x-2< 0\\x+\frac{2}{3}< 0\end{cases}}\Rightarrow\hept{\begin{cases}x< 2\\x< -\frac{2}{3}\end{cases}\Rightarrow x< -\frac{2}{3}< 2\Rightarrow x\in\left\{-1;-2;-3;-4;...\right\}}\)
Vậy x = ...
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a)4x+4-3x+1=14
x+5=14
x=11
b)trường hợp 1 x2-9=0
x2=9
->x=3;-3
-trường hợp 2: x+2=0
x=-2
c)-th1:x2+9=0
x2=-9
->x rỗng
d)xy+2x-y-2=0
(xy-y)+(2x-2)=0
y(x-1)+2(x-1)=0
(y+2)(x-1)=0
th1: y+2=0
y=-2
th2:x-1=0
x=1
(th1: trường hợp 1)
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\(A=\frac{4+x}{x+3}=\frac{x+3+1}{x+3}=1+\frac{1}{x+3}\)(x\(\ne\)-3)
de A thuoc Z ma x thuoc Z \(\Leftrightarrow x+3\in\)Ư(3)={1;-1;3;-3}
ta co bang
x+3 | 1 | -1 | 3 | -3 |
x | -2(tm) | -4(tm) | 0(tm) | -6(tm) |
vay de A thuoc Z khi x \(\in\){-2;-4;0;-6}
co \(|^{ }_{ }x+1|^{ }_{ }\ge0\)voi moi x
\(\Rightarrow|^{ }_{ }x+1|^{ }_{ }-2\ge-2\)hay B \(\ge\)-2
dau "=" xay ra khi x+1=0\(\Leftrightarrow\)x=-1
vay voi x=-1 thi B dat gia tri nho nhat la -2
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\(3\left(x-5\right)-2\left(x+4\right)=-1\)
\(\Rightarrow3x-15-2x-8=-1\)
\(\Rightarrow3x-2x=-1+8+15\)
\(\Rightarrow x=22\)
\(\left|x-3\right|-5^2=\left(-5\right).4\)
\(\Rightarrow\left|x-3\right|=5\)
\(\Rightarrow\orbr{\begin{cases}x-3=5\\x-3=-5\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=8\\x=-2\end{cases}}\)
\(-14-2\left|x-5\right|=0\)
\(\Rightarrow2\left|x-5\right|=-14\)
Vì \(\left|x\right|\ge0\Rightarrow2\left|x-5\right|=-14\)(vô lí)
\(\left(3x+1\right)^2=49\)
\(\Rightarrow\left(3x+1\right)^2=\left(\pm7\right)^2\)
\(\Rightarrow\orbr{\begin{cases}3x+1=7\\3x+1=-7\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=2\\x=-\frac{8}{3}\end{cases}}\)
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(x2-4)(x2-16)=0
<=>x2-4=0<=>x2=4<=>x E {-2;2}
hoặc x2-16=0<=>x2=16<=>x E {-4;4}
vậy x E {-4;-2;2;4}