a)
x (x - 1) + x - 1 = 0
x2 - x + x - 1 = 0
x2 - 1 = 0
x2 = 1
\(\Rightarrow\) x = \(\pm\)1
b)
3( x - 3) - 4x - 12 = 0
3x - 9 - 4x - 12 = 0
-x - 21 = 0
-x = 21
\(\Rightarrow\)x = -21
c)
x3 - 5x = 0
x( x2 - 5) = 0
\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\x2-5=0\Rightarrow x2=5\Rightarrow x\in\varnothing\end{matrix}\right.\)
\(\Rightarrow\)x = 0
d)
(3x - 2)2 - (x + 2)2 = 0
9x2 - 12x + 4 - x2 - 4x - 4 = 0
8x2 - 16x = 0
(làm tương tự như c)
e)
x2 - 9 - 4(x + 3) = 0
x2 - 9 - 4x - 12 = 0
(x2 - 4x + 4) - 13 -12 = 0
(x - 2)2 - 25 = 0
(x - 2)2 = 25
\(\Rightarrow\) x - 2 = 5
\(\Rightarrow\)x = 7
a)x(x-1)+x-1=0
x(x-1)+(x-1)=0
(x-1)(x+1)=0
=>x=1 hoặc x=-1
b)3(x-3)-4x+12=0
3(x-3)-4(x-3)=0
(x-3)(3-4)=0
-(x-3)=0
x+3=0
x=3
c)x3-5x=0
x2(x-5)=0
=>x=0 hoặc x=5
d)(3x-2)2-(x+2)2=0
(3x-2-x-2)(3x-2+x+2)=0
(2x-4)4x=0
=>x=2 hoặc x=0
e)=x2-32-4(x+3)=0
(x-3)(x+3)-4(x+3)=0
(x+3)(x-3-4)=0
(x+3)(x-7)=0
=>x=3 hoặc x=7
f)2(x-2)-x2 +4x -4=0
2(x-2)-(x-2)2=0
(x-2)(2-x+2)=0
(x-2)(4-x)=0
=>x=2 hoặc x=4
