a) \(\Leftrightarrow x^2-x-x^2+2x=5\)
\(\Leftrightarrow x=5\)
b) \(\Leftrightarrow4x\left(x^2-9\right)=0\)
\(\Leftrightarrow4x\left(x-3\right)\left(x+3\right)=0
\)
\(\Leftrightarrow\)\(\left[{}\begin{matrix}4x=0\\x-3=0\\x+3=0\end{matrix}\right.\)
\(\Leftrightarrow\)\(\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)
Vậy x = 0 , x = 3 hoặc x = -3
\(a,\Leftrightarrow x^2-x-x^2+2x=5\\ \Leftrightarrow x=5\\ b,\Leftrightarrow4x\left(x^2-9\right)=0\\ \Leftrightarrow4x\left(x-3\right)\left(x+3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\\ c,\Leftrightarrow2x\left(x-1\right)-\left(x-1\right)^2=0\\ \Leftrightarrow\left(x-1\right)\left(2x-x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\\ d,\Leftrightarrow\left(x^2-9x+14\right)\left(x^2-9x+20\right)-72=0\\ \Leftrightarrow\left(x^2-9x+17\right)^2-3^2-72=0\\ \Leftrightarrow\left(x^2-9x+17\right)^2-81=0\\ \Leftrightarrow\left(x^2-9x+17-9\right)\left(x^2-9x+17+9\right)=0\\ \Leftrightarrow\left(x-8\right)\left(x-1\right)\left(x^2-9x+26\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x=1\\\left(x-\dfrac{9}{2}\right)^2+\dfrac{23}{4}=0\left(vô.n_0\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=8\end{matrix}\right.\)
a) x(x-1)- x2 + 2x =5
x(x-1)-(x2- 2x)=5
x(x-1) -x( x- 2)= 5
x ( x-1) (x-2)=5
=>x=5 ; x-1=5 ; x-2 =5
=>x=5 ; x=6; x=7
b)4x3 - 36x=0
4x(x2- 8)=0
4x=0 hoặc x2 -8 = 0
x = 0 hoặc x2 = 8
x=0 hoặc x= căn 8
=> x thuộc { 0, căn 8}
c) 2x2- 2x= ( x-1)2
( 2x2-2x)- (x-1)= 0
2x(x-1)- 1(x-1)=0
(2x-1)(x-1)=0
=> 2x-1=0 hoặc x-1 =0
=> 2x=1 hoặc x= 1
=> x= 1/2 hoặc x =1
d) (x-7)(x2 -9x+20)(x-2)=72 ( tôi k bt làm)
a) ⇔ x 2 − x − x 2 + 2 x = 5 ⇔ x = 5 b) ⇔ 4 x ( x 2 − 9 ) = 0 ⇔ 4 x ( x − 3 ) ( x + 3 ) = 0 ⇔ ⎡ ⎢ ⎣ 4 x = 0 x − 3 = 0 x + 3 = 0 ⇔ ⎡ ⎢ ⎣ x = 0 x = 3 x = − 3 Vậy x = 0 , x = 3 hoặc x = -3
