Căn 4x2-4x+1=x-1
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\(\left(2x+1\right)^2=x^2\Leftrightarrow\left[{}\begin{matrix}2x+1=x\\2x+1=-x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-\dfrac{1}{3}\end{matrix}\right.\)
\(3x-4x^2+6-8x=x^2+4x+6\Leftrightarrow5x^2+9x=0\Leftrightarrow x=0;x=-\dfrac{9}{5}\)
đk : x khác 0 ; -1
\(\Rightarrow x^2+3x+x^2-x-2=2x\left(x+1\right)\Leftrightarrow2x-2=2x\left(voli\right)\)
Vậy pt vô nghiệm
Ta có
( 4 x 2 + 4 x – 3 ) 2 – ( 4 x 2 + 4 x + 3 ) 2 = ( 4 x 2 + 4 x – 3 + 4 x 2 + 4 x + 3 ) ( 4 x 2 + 4 x – 3 – 4 x 2 – 4 x – 3 ) = ( 8 x 2 + 8 x ) . ( - 6 )
= 8.x(x + 1).(-6)
= -48x(x + 1) nên m = -48 < 0
Đáp án cần chọn là: B
a) ⇔ \(4x^2+4x-x-1=0\)
⇔ \(4x^2+3x-1=0\)
⇔ \(4x(x+1)-(x+1)=0\)
⇔ \((x+1)(4x-1)=0\)
⇒ \(\left[{}\begin{matrix}x=-1\\x=\dfrac{1}{4}\end{matrix}\right.\)
Vậy...
b) \(x^3-4x^2+4x=0\)
⇔ \(x^2(x-2)-2x(x-2)=0\)
⇔ \((x-2)(x^2-2x)=0\)
⇒ \(\left[{}\begin{matrix}x=2\\x=0\end{matrix}\right.\)
Vậy...
c) \(x^2-3x+2=0\)
⇔ \(x(x-2)-(x-2)=0\)
⇔ \((x-1)(x-2)=0\)
⇒ \(\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
Vậy...
\(a,\Leftrightarrow x\left(2x-7\right)+2\left(2x-7\right)=0\\ \Leftrightarrow\left(x+2\right)\left(2x-7\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=\dfrac{7}{2}\end{matrix}\right.\\ b,\Leftrightarrow x\left(x^2-9\right)=0\\ \Leftrightarrow x\left(x-3\right)\left(x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\\ c,\Leftrightarrow\left(2x-1\right)\left(2x+1\right)-2\left(2x-1\right)^2=0\\ \Leftrightarrow\left(2x-1\right)\left(2x+1-4x+2\right)=0\\ \Leftrightarrow\left(2x-1\right)\left(-2x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{3}{2}\end{matrix}\right.\\ d,\Leftrightarrow x^2\left(x-1\right)-4\left(x-1\right)^2=0\\ \Leftrightarrow\left(x-1\right)\left(x^2-4x+4\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x-2\right)^2=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
1: Ta có: \(\left(x+3\right)\left(x^2-3x+9\right)-\left(x^3+54\right)\)
\(=x^3+27-x^3-54\)
=-27
2: Ta có: \(\left(2x+y\right)\left(4x^2-2xy+y^2\right)-\left(2x-y\right)\left(4x^2+2xy+y^2\right)\)
\(=8x^3+y^3-8x^3+y^3\)
\(=2y^3\)
\(1,=x^3+270-x^3-54=-27\\ 2,=8x^3+y^3-8x^3+y^3=2y^3\\ 3,=x^3-3x^2+3x-1-x^3-8+3x^2-48=3x-57\\ 4,=x^3-x-x^3-1=-x-1\\ 5,=8x^3-5\left(8x^3+1\right)=-32x^3-5\\ 6,=27+x^3-27=x^3\\ 7,làm.ở.câu.3\\ 8,=x^3-6x^2+12x-8+6x^2-12x+6-x^3-1+3x\\ =3x-3\)
\(\sqrt{4x^2-4x+1}=x-1\)
\(\Leftrightarrow\sqrt{\left(2x-1\right)^2}=x-1\)
\(\Leftrightarrow\left|2x-1\right|=x-1\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=x-1\\2x-1=1-x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{3}\end{matrix}\right.\)
\(\sqrt{4x^2-4x+1}=x-1\)
\(\left|2x-1\right|=x-1\)
TH1: \(x< \dfrac{1}{2}\) phương trình trên trở thành:
\(1-2x=x-1\Leftrightarrow x=\dfrac{2}{3}\) (không thỏa mãn \(x< \dfrac{1}{2}\))
TH2: \(x\ge\dfrac{1}{2}\) phương trình trên trở thành:
\(2x-1=x-1\Leftrightarrow x=0\) (không thỏa mãn \(x\ge\dfrac{1}{2}\))
Vậy phương trình đã cho vô nghiệm.