Tim x biet (x+1)^3-(x-1)^3 - 6(x-1)^3=0
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Bài 2:
a: \(\Leftrightarrow\left(x-2\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\)
- a, Do \(\left[3x-15\right]^7=0\)
=> \(3x-15=0\)
=> \(3x=0+15\)
=> \(3x=15\)
=> \(x=15:3\)
=> \(x=5\)
\(\left(3x-5\right)^7=0\)
\(\Rightarrow3x-5=0\)
\(\Rightarrow3x=5\)
\(\Rightarrow x=\frac{5}{3}\)
dễ
ai đi qua tick cho mình nha
ai tick thì may mắn trọn đời
1: \(16x^2-9\left(x+1\right)^2=0\)
=>\(\left(4x\right)^2-\left(3x+3\right)^2=0\)
=>(4x-3x-3)(4x+3x+3)=0
=>(x-3)(7x+3)=0
=>\(\left[\begin{array}{l}x-3=0\\ 7x+3=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=3\\ x=-\frac37\end{array}\right.\)
2: \(\left(5x-4\right)^2-49x^2=0\)
=>\(\left(5x-4\right)^2-\left(7x\right)^2=0\)
=>(5x-4-7x)(5x-4+7x)=0
=>(12x-4)(-2x-4)=0
=>4(3x-1)*(-2)(x+2)=0
=>(3x-1)(x+2)=0
=>\(\left[\begin{array}{l}3x-1=0\\ x+2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac13\\ x=-2\end{array}\right.\)
3: \(5x^3-20x=0\)
=>\(5x\left(x^2-4\right)=0\)
=>x(x-2)(x+2)=0
=>\(\left[\begin{array}{l}x=0\\ x-2=0\\ x+2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=2\\ x=-2\end{array}\right.\)
a, \(16x^2-9\left(x+1\right)^2=0\)
\(\Leftrightarrow\left(4x\right)^2-\left(3x+3\right)^2=0\Leftrightarrow\left(4x-3x-3\right)\left(4x+2x+3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(6x+3\right)=0\Leftrightarrow x=-\frac{1}{2};x=3\)
b, \(\left(5x-4\right)^2-49x^2=0\Leftrightarrow\left(5x-4-7x\right)\left(5x-4+7x\right)=0\)
\(\Leftrightarrow\left(-2x-4\right)\left(12x-4\right)=0\Leftrightarrow x=-2;x=\frac{1}{3}\)
c, \(5x^3-20x=0\Leftrightarrow5x\left(x^2-4\right)=0\)
\(\Leftrightarrow5x\left(x-2\right)\left(x+2\right)=0\Leftrightarrow x=0;x=\pm2\)
Sửa đề: \(\left(x+1\right)^3-\left(x-1\right)^3-6\left(x-1\right)^2=0\)
Ta có: \(\left(x+1\right)^3-\left(x-1\right)^3-6\left(x-1\right)^2=0\)
=>\(x^3+3x^2+3x+1-\left(x^3-3x^2+3x-1\right)-6\left(x^2-2x+1\right)=0\)
=>\(x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\left(x^2-2x+1\right)=0\)
=>\(6x^2+2-6x^2+12x-6=0\)
=>12x-4=0
=>12x=4
=>\(x=\frac{4}{12}=\frac13\)