Tìm x: (x - 6).(x + 2) < 0
\(1,\)
\(2x\left(x-3\right)-\left(3-x\right)=0\)
\(\Leftrightarrow2x\left(x-3\right)+\left(x-3\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(x-3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=0\\x-3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=3\end{cases}}\)
\(2,\)
\(3x\left(x+5\right)-6\left(x+5\right)=0\)
\(\Leftrightarrow\left(3x-6\right)\left(x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\x+5=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-5\end{cases}}\)
\(3,\)
\(x^4-x^2=0\)
\(\Leftrightarrow x^2\left(x^2-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2=0\\x^2-1=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)
\(4,\)
\(x^2-2x=0\)
\(\Leftrightarrow x\left(x-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
\(5,\)
\(x\left(x+6\right)-10\left(x-6\right)=0\)
\(\Leftrightarrow x^2+6x-10x+60=0\)
\(\Leftrightarrow x^2-4x+60=0\)
\(\Leftrightarrow x^2-4x+4+56=0\)
\(\Leftrightarrow\left(x-2\right)^2=-56\)(Vô lý)
=> Phương trình vô nghiệm
Tìm x,biết
1) 3x^2 - 4x = 0
2) (x^2 - 5x) + x - 5 = 0
3) x^2 - 5x + 6 = 0
4) 5x(x-3) - x+3 = 0
5) x^2 - 2x + 5 = 0
6) x^2 + x -6 = 0
Answer:
\(3x^2-4x=0\)
\(\Rightarrow x\left(3x-4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{4}{3}\end{cases}}\)
\(\left(x^2-5x\right)+x-5=0\)
\(\Rightarrow x\left(x-5\right)+\left(x-5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-5=0\\x+1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=-1\end{cases}}\)
\(x^2-5x+6=0\)
\(\Rightarrow x^2-2x-3x+6=0\)
\(\Rightarrow\left(x^2-2x\right)-\left(3x-6\right)=0\)
\(\Rightarrow x\left(x-2\right)-3\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\x-3=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=3\end{cases}}\)
\(5x\left(x-3\right)-x+3=0\)
\(\Rightarrow5x\left(x-3\right)-\left(x-3\right)=0\)
\(\Rightarrow\left(5x-1\right)\left(x-3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}5x-1=0\\x-3=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{5}\\x=3\end{cases}}\)
\(x^2-2x+5=0\)
\(\Rightarrow\left(x^2-2x+1\right)+4=0\)
\(\Rightarrow\left(x-1\right)^2=-4\) (Vô lý)
Vậy không có giá trị \(x\) thoả mãn
\(x^2+x-6=0\)
\(\Rightarrow x^2+3x-2x-6=0\)
\(\Rightarrow x.\left(x+3\right)-2\left(x+3\right)=0\)
\(\Rightarrow\left(x-2\right)\left(x+3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\x+3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2\\x=-3\end{cases}}}\)
Tìm x=? x:=6;If(x mod 2 >< 0) and (x>0) Then x:=x*2 else x:=x-1;
1, Tìm x, biết \(x^2\) – 36 = 0
A. x = 6. B. x = -6.
C. x = 6; x = -6. D. x = 36 hoặc x = - 36.
2, Tìm x, biết \(x^3\) – 3\(x^2\) + 3x - 1 = 0
A. x = 1. B. x = -1. C. x = 0. D. x = 2.
bài 7 tìm x
1,x(x+3)-5(x+3)=0 2,5x(x-1)=x-1
3,(x+1)=(x+1)\(^2\) 4,x(2x-3)-2(3-2x)=0
5,\(\left(x-2\right)^2-4=0\) 6,\(36x^2=49\)
7,\(2x\left(x-6\right)-x+6=0\) 8,\(3x\left(2x-1\right)-24x+12=0\)
9,\(x^2-6x+8=0\) 10,\(x^2+2x-15=0\)
1: =>(x+3)(x-5)=0
=>x=5 hoặc x=-3
2: =>(x-1)(5x-1)=0
=>x=1/5 hoặc x=1
5: =>(x-4)*x=0
=>x=0 hoặc x=4
10: =>(x+5)(x-3)=0
=>x=3 hoặc x=-5
9: =>(x-2)(x-4)=0
=>x=2 hoặc x=4
7: =>(x-6)(2x-1)=0
=>x=1/2 hoặc x=6
8: =>(2x-1)(3x-12)=0
=>x=4 hoặc x=1/2
Tìm x,y biết :
|x-4|+|6-x|=0
|x+1|-|x-2|=0
|x+2|-|x-3|=0
|x-2|-|x-3|=0
|2x-1|-|x+1|=0
4x-6+2x=12
|x - 4| + |6 - x| = 0
|x - 4| ; |6 - x| \(\ge\) 0
=> |x - 4| = |6 - x| = 0
|x - 4| = 0 => x= 4
|6 - x| = 0 => x= 6
Vì \(4\ne6\) n ê n không có giá trị của x
Bạn làm các câu khác tương tự
Tìm x :
a) x(x - 1 ) = 0
b) 3x^2 - 6x = 0
c) x( x - 6 ) + 10( x - 6 ) = 0
d) x^3 - x = 0
a) x(x - 1) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-1=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
b) 3x2 - 6x = 0
=> 3x.(x - 2) = 0
=> x.(x - 2) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-2=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=2\end{array}\right.\)
c) x(x - 6) + 10(x - 6) = 0
=> (x - 6)(x + 10) = 0
=> \(\left[\begin{array}{nghiempt}x-6=0\\x+10=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=6\\x=-10\end{array}\right.\)
d) x3 - x = 0
=> x.(x2 - 1) = 0
=> x.(x - 1).(x + 1) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-1=0\\x+1=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=1\\x=-1\end{array}\right.\)
a)
\(x\left(x-1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-1=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
Vậy x=0 ; x =1
b)
\(3x^2-6x=0\)
\(\Rightarrow3x\left(x-2\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-2=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=2\end{array}\right.\)
Vậy x=0 ; x =2
c)
\(x\left(x-6\right)+10\left(x-6\right)=0\)
\(\Rightarrow\left(x-6\right)\left(x+10\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x-6=0\\x+10=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=6\\x=-10\end{array}\right.\)
Vậy x=6 ; x = -10
d)
\(x^3-x=0\)
\(\Rightarrow x\left(x^2-1\right)=0\)
\(\Rightarrow x\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-1=0\\x+1=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\\x=-1\end{array}\right.\)
Vậy x = 0 ; x = 1 ; x= - 1
a,\(x\left(x-1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-1=0\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
b,\(3x^2-6x=0\)
\(\Rightarrow3x\left(x-2\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}3x=0\\x-2=0\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=2\end{array}\right.\)
c,\(x\left(x-6\right)+10\left(x-6\right)=0\)
\(\Rightarrow\left(x+10\right)\left(x-6\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x-6=0\\x+10=0\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=6\\x=-10\end{array}\right.\)
d,\(x^3-x=0\)
\(\Rightarrow x^2\left(x-1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x^2=0\\x-1=0\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
Tìm x, y thuộc Z biết:
a) x ( x + 6 ) = 0
b) ( x − 3 ) . ( y + 7 ) = 0
c) ( x − 2 ) ( x 2 + 2 ) = 0
a) x ( x + 6 ) = 0 ⇔ x = 0 x + 6 = 0 ⇔ x = 0 x = − 6
Vậy x = 0 hoặc x = - 6
b) ( x − 3 ) . ( y + 7 ) = 0 ⇔ x − 3 = 0 y + 7 = 0 ⇔ x = 3 y = − 7
Vậy x = 3 hoặc x = -7
c) ( x − 2 ) ( x 2 + 2 ) = 0 ⇔ x − 2 = 0 x 2 + 2 = 0 ⇔ x = 2 x 2 = − 2 ( L )
Vậy x = 2
Tìm x:
a)x.(x-1)-(x-2)2=2
b)x2-9=(x-3).(6-x)
c)x2-x-6=0
Tìm x:
a)x.(x-1)-(x-2)2=2
b)x2-9=(x-3).(6-x)
c)x2-x-6=0
\(a,\Leftrightarrow x^2-x-x^2+4x-4=2\\ \Leftrightarrow3x=6\Leftrightarrow x=2\\ b,\Leftrightarrow\left(x-3\right)\left(x+3\right)-\left(x-3\right)\left(6-x\right)=0\\ \Leftrightarrow\left(x-3\right)\left(x+3-6+x\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{3}{2}\end{matrix}\right.\\ c,\Leftrightarrow x^2+2x-3x-6=0\\ \Leftrightarrow\left(x+2\right)\left(x-3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=3\end{matrix}\right.\)