Tìm x biết (3x-15)7=0 ;42x-6=1 ;(3-x)10x/(3-x)20=1(x khác 3) (x-6)3=(x-6)2
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1) x (x-2016) + 2015 (2016-x) = 0
x (x-2016) - 2015 (x- 2016) = 0
(x-2015)(x-2016) =0
\(\Rightarrow\orbr{\begin{cases}x-2015=0\\x-2016=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2015\\x=2016\end{cases}}}\)
Vậy x= 2015; 2016
2) -5x (x-15) + (15-x) = 0
-5x (x-15) - (x-15) =0
(-5x -1) (x-15) =0
\(\Rightarrow\orbr{\begin{cases}-5x-1=0\\x-15=0\end{cases}\Rightarrow\orbr{\begin{cases}-5x=1\\x=15\end{cases}\Rightarrow}\orbr{\begin{cases}x=-\frac{1}{5}\\x=15\end{cases}}}\)
Vậy x= -1/5; 15
3) 3x (3x-7) - (7-3x) =0
3x(3x-7) + (3x -7) =0
(3x+1) (3x-7) =0
\(\Rightarrow\orbr{\begin{cases}3x+1=0\\3x-7=0\end{cases}\Rightarrow\orbr{\begin{cases}3x=-1\\3x=7\end{cases}\Rightarrow}\orbr{\begin{cases}x=-\frac{1}{3}\\x=\frac{7}{3}\end{cases}}}\)
Vậy x= -1/3 ; 7/3
Tìm x biết
1. 2(5x-8)-3(4x-5)=4(3x-4)+11
2. (2x+1)2-(4x-1).(x-3)-15=0
3. (3x-1).(2x-7)-(1-3x).(6x-5)=0
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1) \(\Rightarrow10x-16-12x+15=12x-16+11\)
\(\Rightarrow14x=4\Rightarrow x=\dfrac{2}{7}\)
2) \(\Rightarrow4x^2+4x+1-4x^2+13x-3-15=0\)
\(\Rightarrow17x=17\Rightarrow x=1\)
3) \(\Rightarrow\left(3x-1\right)\left(2x-7+6x-5\right)=0\)
\(\Rightarrow\left(2x-3\right)\left(3x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
2: Ta có: \(\left(2x+1\right)^2-\left(4x-1\right)\left(x-3\right)-15=0\)
\(\Leftrightarrow4x^2+4x+1-4x^2+12x+x-3-15=0\)
\(\Leftrightarrow17x=17\)
hay x=1
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a) (x – 45).27 = 0
=> x - 45 = 0
=> x = 45
b) 23.(42- x) = 23
=> 42- x = 1
=> x = 41
c. 3x – 5=7
=> 3x = 12
=> x = 4
e. 15 – 5x=10
=> 5x = 5
=> x = 1
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a) -15÷x=3
x=-15÷3
x=-5
b) -3x+8=-7
-3x . =-15
x. =-15÷-3
x. = 5
c) ( x-6) (7- x) =0
Suy ra: * x-6 =0=) x=6
*7-x=0=) x=7
Vậy x=6;7
a, -15:x=3
\(\Rightarrow x=-15:3\)
\(\Rightarrow x=-5\)
Vậy x=-5
b,-3x+8=-7
\(\Rightarrow-3x=-7-8\)
\(\Rightarrow-3x=15\)
\(\Rightarrow x=15:\left(-3\right)\)
\(\Rightarrow x=5\)
Vậy x=5
c, (x-6)(7-x)=0
\(\Rightarrow\orbr{\begin{cases}x-6=0\\7-x=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=0+6\\x=7-0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
Vậy \(\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
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1.Tìm x,y biết:
a,|x-7|=15
|x-7|=15 hoặc |x-7|=-15
Với |x-7|=15
x=15+7
x=22
Với |x-7|=-15
x=(-15)+7
x=-(15+7)
x=-22
c,-|3x-2|=-1
-|3x|=-(1+2)
-|3x|=-3
x=(-3):(-3)
x=-9
d,|x-4|-(-3)=2016
|x-4|=2016-(-3)
|x-4|=2016-3
|x-4|=2013
|x-4|=2013 hoặc |x-4|=-2013
Với |x-4|=2013
x=2013+4
x=2017
Với|x-4|=-2013
x=(-2013)-4
x=-(2013+4)
x=-2017
2 Tìm x biết :
b,x2+x-6=0
x2+x-6=0
x2+x=0+6
x2+x=6
22+2=6
x=2
a) \(\Rightarrow\orbr{\begin{cases}x-7=15\\x-7=-15\end{cases}\Rightarrow\orbr{\begin{cases}x=22\\x=-8\end{cases}}}\)
KL \(\orbr{\begin{cases}x=22\\x=-8\end{cases}}\)
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a,x.(x+7)=0
suy ra x=o hoặc x+7=0
vs x+7=0
x=0+7
x=7
vậy x=0 hoặc x=7
b(2+2x)(7-x)=0
suy ra 2+2x=0 hoặc 7-x=0
vs2+2x=0 vs7-x=0
2x =0-2 x=0+7
2x =(-2) x=7
x=(-2);2
x=-1
vậy x=-1 hoặc x=7
d(x^2-9)(3x+15)=0
suy ra x^2-9=0 hoặc 3x+15=0
vsx^2-9=0 vs 3x+15=0
x^2 =0+9 3x =0-15
x^2 =9 3x =-15
x^2 =3^2 x=(-15):3
suy ra x=3 hoặc x=-3 x=-5
vậy x=3 x=-3 hoặc x=-5
e,(4x-8)(x^2+1)=0
suy ra4x-8=0 hoặc x^2+1=0
vs 4x-8=0 vs x^2+1=0
4x =0+8 x^2 =0-1
4x =8 x^2 =-1
x =8:4 x^2 =-1^2 hoặc 1^2
x =2 suy ra x=-1 hoặc x=1
vậy x=2, x=-1 hoặc x=1
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\(2+3x=-15-19\)
\(\Rightarrow3x=-15-19-2\)
\(\Rightarrow3.x=-36\)
\(\Rightarrow x=-13\)
\(7-\left|x\right|\left(2x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}7-\left|x\right|=0\\2x-4=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}\left|x\right|=7\\2x=4\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\pm7\\x=2\end{cases}}\)
\(\left|x+1\right|-3=0\)
\(\Rightarrow\left|x+1\right|=3\)
\(\Leftrightarrow\orbr{\begin{cases}x+1=3\\x+1=-3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-4\end{cases}}\)
(3x - 15)7 = 0
=> 3x - 15 = 0
=> 3x = 15
=> x = 5
42x-6 = 40
=> 2x - 6 = 0
=> 2x = 6
=>x = 3