a) 4x : 17 = 0
b) 7x - 8 = 713
c) 8( x - 3) = 0
d) 0 : x = 0
Tìm x biết:
a, 16x² – 9(x + 1)²= 0
b, x2 (x – 1) – 4x2 + 8x – 4 = 0
c, x(2x – 3) – 2(3 – 2x) = 0
d, (x – 3)(x² + 3x + 9) – x(x + 2)(x – 2) = 1
e, 4x² + 4x – 6 = 2
f, 2x² + 7x + 3 = 0
e: ta có: \(4x^2+4x-6=2\)
\(\Leftrightarrow4x^2+4x-8=0\)
\(\Leftrightarrow\left(x+2\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=1\end{matrix}\right.\)
f: Ta có: \(2x^2+7x+3=0\)
\(\Leftrightarrow\left(x+3\right)\left(2x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-\dfrac{1}{2}\end{matrix}\right.\)
Bài 2: Tìm x, biết:
a) 4x(x + 1) = 8( x + 1) c) x2 – 6x + 8 = 0
b) x3 + x2 + x + 1 = 0 d) x3 – 7x – 6 = 0
\(a,\Leftrightarrow\left(4x-8\right)\left(x+1\right)=0\\ \Leftrightarrow4\left(x-2\right)\left(x+1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\\ b,\Leftrightarrow\left(x+1\right)\left(x^2+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-1\\x^2=-1\left(vô.lí\right)\end{matrix}\right.\Leftrightarrow x=-1\\ c,\Leftrightarrow x^2-2x-4x+8=0\\ \Leftrightarrow\left(x-2\right)\left(x-4\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=4\end{matrix}\right.\\ d,\Leftrightarrow x^3-3x^2+3x-9x+2x-6=0\\ \Leftrightarrow\left(x-3\right)\left(x^2+3x+2\right)=0\\ \Leftrightarrow\left(x-3\right)\left(x^2+x+2x+2\right)=0\\ \Leftrightarrow\left(x-3\right)\left(x+1\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=3\\x=-1\\x=-2\end{matrix}\right.\)
a) \(\Rightarrow4\left(x+1\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\)
b) \(\Rightarrow x^2\left(x+1\right)+\left(x+1\right)=0\)
\(\Rightarrow\left(x+1\right)\left(x^2+1\right)=0\)
\(\Rightarrow x=-1\left(do.x^2+1\ge1>0\right)\)
c) \(\Rightarrow x\left(x-4\right)-2\left(x-4\right)=0\)
\(\Rightarrow\left(x-4\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=4\\x=2\end{matrix}\right.\)
d) \(\Rightarrow x^2\left(x-3\right)+3x\left(x-3\right)+2\left(x-3\right)\)
\(\Rightarrow\left(x-3\right)\left(x^2+3x+2\right)=0\)
\(\Rightarrow\left(x-3\right)\left(x+1\right)\left(x+2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-2\\x=-1\end{matrix}\right.\)
Tìm x:
a) 5x(x-2)+(2-x)=0
b) x(2x-5)-10x+25=0
c) \(\dfrac{25}{16}\)-4x2+4x-1=0
d)x4+2x2-8=0
a) \(\text{5x(x-2)+(2-x)=0}\)
\(\Rightarrow5x\left(x-2\right)-\left(x-2\right)=0\\ \Rightarrow\left(x-2\right)\left(5x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-2=0\\5x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{1}{5}\end{matrix}\right.\)
b) \(\text{x(2x-5)-10x+25=0}\)
\(\Rightarrow x\left(2x-5\right)-5\left(2x-5\right)=0\\ \Rightarrow\left(x-5\right)\left(2x-5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-5=0\\2x-5=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=5\\x=2,5\end{matrix}\right.\)
c) \(\dfrac{25}{16}-4x^2+4x-1=0\)
\(\Rightarrow\dfrac{9}{16}-4x^2+4x=0\)
\(\Rightarrow-4x^2+4x+\dfrac{9}{16}=0\)
\(\Rightarrow-4x^2-\dfrac{1}{2}x+\dfrac{9}{2}x+\dfrac{9}{16}=0\)
\(\Rightarrow\left(-4x^2-\dfrac{1}{2}x\right)+\left(\dfrac{9}{2}x+\dfrac{9}{16}\right)=0\)
\(\Rightarrow-\dfrac{1}{2}x\left(8x+1\right)+\dfrac{9}{16}\left(8x+1\right)=0\)
\(\Rightarrow\left(-\dfrac{1}{2}x+\dfrac{9}{16}\right)\left(8x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}-\dfrac{1}{2}x+\dfrac{9}{16}=0\\8x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{8}\\x=\dfrac{-1}{8}\end{matrix}\right.\)
a) \(5x\left(x-2\right)+\left(2-x\right)=0\)
\(\Rightarrow5x\left(x-2\right)-\left(x-2\right)=0\)
\(\Rightarrow\left(x-2\right)\left(5x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-2=0\\5x-1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{1}{5}\end{matrix}\right.\)
b) \(x\left(2x-5\right)-10x+25=0\)
\(\Rightarrow x\left(2x-5\right)-5\left(2x-5\right)=0\)
\(\Rightarrow\left(x-5\right)\left(2x-5\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-5=0\\2x-5=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=5\\x=\dfrac{5}{2}\end{matrix}\right.\)
c) \(\dfrac{25}{16}-4x^2+4x-1=0\)
\(\Rightarrow-4x^2+4x+\dfrac{9}{16}=0\)
\(\Rightarrow\left(x-\dfrac{9}{8}\right)\left(x+\dfrac{1}{8}\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{9}{8}=0\\x+\dfrac{1}{8}=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{8}\\x=-\dfrac{1}{8}\end{matrix}\right.\)
d) \(x^4+2x^2-8=0\)
\(\Rightarrow\left(x^4+2x^2+1\right)-9=0\)
\(\Rightarrow\left(x^2+1\right)^2-3^2=0\)
\(\Rightarrow\left(x^2+1-3\right)\left(x^2+1+3\right)=0\)
\(\Rightarrow\left(x^2-2\right)\left(x^2+4\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x^2-2=0\\x^2+4=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x^2=2\\x^2=-4\end{matrix}\right.\) \(\Rightarrow x^2=2\) \(\Rightarrow x=\pm\sqrt{2}\)
a) 4x : 17 =0
b) 7x - 8 = 713
c) 8(x - 3) = 0
Tìm x , biết :
a, 7x - 8 = 713
b, 8( x - 3 ) = 0
4x :17 = 0
a, x= 103
b, x= 3
c,x=0
Nếu thấy đúng thì k cho mk nhé!
a)7x-8=713
7x =713+8
7x =721
x =721:7
x =103
Vậy x=103
b)8(x-3)=0
x-3=0:8
x-3=0
x=0+3
x=3
Vậy x=0
4x:7=0
4x =0*7
4x =0
x =0:4
x =0
Vậy x=0
a/ 7x - 8 = 713
7x = 713 + 8
7x = 721
x = 721 : 7
x = 103
b/ 8 ( x -3 ) = 0
x - 3 = 0
x = 0+3
x = 3
4x : 17 = 0
4x = 0 x 17
4 x = 0
x = 0
Tìm x a, 4x : 17 = 0 b, 7x - 8 = 713 c, 8(x - 3) = 0 d, 0 : x = 0
a) \(4x:17=0\)
\(4x=0\)
\(x=0\)
vay \(x=0\)
b) \(7x-8=713\)
\(7x=713+8\)
\(7x=721\)
\(x=103\)
vay \(x=103\)
c) \(8\left(x-3\right)=0\)
\(8x-24=0\)
\(8x=24\)
\(x=3\)
vay \(x=3\)
d) \(0:x=0\)
\(\Rightarrow x\in R\) va \(x\ne0\)
vay \(x\in R\)va \(x\ne0\)
a, 4x : 17 = 0
=>4x = 0
x = 0 : 4
x = 0
Vậy x = 0 .
b, 7x - 8 = 713
7x = 713 + 8
7x = 721
x = 721 : 7
x = 103
Vậy x = 103 .
c, 8( x - 3 ) = 0
=> x - 3 = 0
x = 0 + 3
x = 3
Vậy x = 3 .
d, 0 : x = 0
=> x là các số tự nhiên khác 0
=> X ∈ N*
Chúc học tốt !
a. 4x : 17 = 0
b. 7x - 8 = 713
c. 8(x - 3) = 0
a) 4X : 17 = 0
4X= 0 x17
4X = 0
X = 0 : 4
X = 0
Vậy X = 0
b) 7X - 8 = 713
7X = 713 + 8
7X = 721
X = 721 : 7
X = 103
Vậy X = 103
c) 8 ( X - 3 ) = 0
X - 3 = 0 : 8
X - 3 = 0
X = 0 + 3
X = 3
Vậy X = 3
a. 4x : 17 = 0
=> 4x=0.17
=> 4x=0
=> x=0:4
=> x=0
b. 7x - 8 = 713
=> 7x=713+8
=> 7x = 721
=> x = 721 : 7
=> x= 103
c. 8(x - 3) = 0
=> x-3=0:8
=> x-3=0
=> x=0+3
=> x=3
a. 4x : 17= 0
4x = 0 : 17
4x = 0
x = 0 : 4
x = 0
b. 7x - 8 = 713
7x = 713 + 8
7x = 721
x = 721 : 7
x = 103
c . 8 ( x - 3 ) = 0
x - 3 = 0 : 8
x - 3 = 0
x = 0 + 3
x = 3
Bài 7. Tìm x,biết:
a) x-3x2=0 e) 5x(3x-1)+x(3x-1)-2(3x-1)=0
b) (x+3)2-x(x-2)=13 c) (x-4)2-36=0
d) x2-7x+12=0 g) x2-2018x-2019=0
Bài 8. Tìm x, biết
a) (2x-1)2=(x+5)2 b) x2-x+1/4
c) 4x4-101x2+25=0 d) x3-3x2+9x-91=0
a) 4x : 17 = 0
b) 7x - 8 = 713
c) 8( x - 3 ) = 0
a) 4x:17=0
4x=0x17
4x=0
x=0:4
x=0
b)7x-8=713
7x=213+8
7x=221
x=221:7
x=221/7
c)8(x-3)=0
8x - 8x3 = 0
8x -24=0
8x=0+24
8x=24
x=24:8
x=3