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\(\left(4x-1\right)^2+\left(x+3\right)^2=16x^2-8x+1+x^2+6x+9\)
\(=17x^2-2x+10\)
\(\left(x-y+1\right)^3=x^3-y^3+1-3x^2y+3xy^2+3x^2+3x+3y^2-3y-6xy\)
\(\left(4x-1\right)^2+\left(x+3\right)^2=16x^2-8x+1+x^2+6x+9\) \(=17x^2-2x+10\)
\(\left(x-y+1\right)^3=\left(x-y\right)^3+3\left(x-y\right)^2+3\left(x-y\right)+1\)
1/ \(\left(2x-1\right)^2-3\left(2x-1\right)^2=0\)
\(\left(2x-1\right)^2\left(1-3\right)=0\)
\(\left(2x-1\right)^2\cdot\left(-2\right)=0\)
\(\Rightarrow\text{ }\left(2x-1\right)^2=0\)
\(2x-1=0\)
\(2x=0+1=1\)
\(x=\frac{1}{2}\)
1) \(\left(2x-1\right)^2-3\left(2x-1\right)^2=0\)
=> \(\left(2x-1\right)^2\left(1-3\right)=0\)
=> \(\left(2x-1\right)^2.\left(-2\right)=0\)
=> \(\left(2x-1\right)^2=0\)
=> \(2x-1=0\)
=> \(2x=1\)
=> \(x=1:2=\frac{1}{2}\)
\(\left(x-y+1\right)^3=\left(x-y\right)^3+3\left(x-y\right)^2+3\left(x-y\right)+1\)
\(=x^3-3x^2y+3xy^2-y^3+3x^2-6xy+3y^2+3x-3y+1\)
Mong là lần này không làm nhầm:v
thì bạn chỉ cần khai triển hằng đẳng thức là được thôi,nếu không biết thì cứ gõ lên mạng
Bài Làm:
\(1,\left(2x-1\right)^2-3\left(2x-1\right)^2=0\)
\(\Leftrightarrow-2\left(2x-1\right)^2=0\)
\(\Leftrightarrow\left(2x-1\right)^2=0\)
\(\Leftrightarrow2x-1=0\)
\(\Leftrightarrow x=\frac{1}{2}\)
Vậy ...
\(2,\left(x-1\right)^2\left(x+1\right)=x+1\)
\(\Leftrightarrow\left(x-1\right)^2\left(x+1\right)-\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left[\left(x-1\right)^2-1\right]=0\)
\(\Leftrightarrow\left(x+1\right)\left[x^2-2x+1-1\right]=0\)
\(\Leftrightarrow\left(x+1\right)\left(x^2-2x\right)=0\)
\(\Leftrightarrow x\left(x+1\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+1=0\\x-2=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=2\end{matrix}\right.\)
Vậy ...
\(3,x^4-3x^2=x^2\)
\(\Leftrightarrow x^4-3x^2-x^2=0\)
\(\Leftrightarrow x^4-4x^2=0\)
\(\Leftrightarrow x^2\left(x^2-4\right)=0\)
\(\Leftrightarrow x^2\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2=0\\x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)
Vậy ...
Chúc pạn hok tốt!!!
x(y - z) + 2(z - y)
= x(y - z) - 2(y - z)
= (x - 2)(y - z)
(2x - 3y)(x - 2) - (x + 3)(3y - 2x)
= (2x - 3y)(x - 2) + (x + 2)(2x - 3y)
= (2x - 3y)(x - 2 + x + 2)
= 2x(2x - 3y)
\(1.\)
\(4x^2-12x+9\)
\(=\left(2x\right)^2-12x+3^2=\left(2x-3\right)^2\)
\(2.\)
\(7x^2-7xy-5x+5y\)
\(=7x\left(x-y\right)-5\left(x-y\right)\)
\(\left(7x-5\right)\left(x-y\right)\)
\(3.\)
\(x^3-9x\)
\(=x\left(x^2-9\right)\)
\(=x\left(x-3\right)\left(x+3\right)\)
\(4.\)
\(5x\left(x-y\right)-15\left(x-y\right)\)
\(=\left(5x-15\right)\left(x-y\right)\)
\(=5\left(x-3\right)\left(x-y\right)\)
\(5.\)
\(2x^2+x\)
\(=2x\left(x+1\right)\)
\(6.\)
\(x^3+27\)
\(=\left(x+3\right)\left(x^2-3x+9\right)\)
\(7.\)
\(2x^2-4xy+2y^2-32\)
\(=2\left(x^2-2xy+y^2-16\right)\)
\(=2\left[\left(x^2-2xy+y^2\right)-16\right]\)
\(=2\left[\left(x-y\right)^2-4^2\right]\)
\(=2\left(x-y+4\right)\left(x-y-4\right)\)
\(8.\)
\(x^3-4x-3x^2+12\)
\(=\left(x-3\right)\left(x-2\right)\left(x+2\right)\)
\(9.\)
\(2x+2y+x^2-y^2\)
\(=2\left(x+y\right)+\left(x-y\right)\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y+2\right)\)
\(10.\)
\(x^2y-2xy+y\)
\(=y\left(x^2-2x+1\right)\)
\(=y\left(x-1\right)^2\)
\(11.\)
\(y^2+2y\)
\(=y\left(y+2\right)\)
\(12.\)
\(y^2-x^2-6y-6x\)
\(=\left(y-x\right)\left(y+x\right)-6\left(y+x\right)\)
\(=\left(y+x\right)\left(y-x-6\right)\)
\(13.\)
\(x^3-3x\)
\(=x\left(x^2-3\right)\)
\(=x\left(x-\sqrt{3}\right)\left(x+\sqrt{3}\right)\)
\(14.\)
\(2x-xy+2z-yz\)
\(=x\left(2-y\right)+z\left(2-y\right)\)
\(=\left(2-y\right)\left(x+z\right)\)
Xong
Bạn kiểm tra lại đề nhé!
Nếu viết theo thứ tự trên thì 2 phân số cuối là: \(\frac{x-1}{2012}\)và \(\frac{x}{2013}\)
Đề là sao đây bạn
khai triển ạ