Phân tích đa thức thành nhân tử\(x^2-\frac{5}{3}x-\frac{2}{3}\)
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\(x^3+\frac{3}{2}x^2+\frac{3}{4}x+\frac{1}{8}=\left(x+\frac{1}{2}\right)^3\)
Bạn ghi sai đề nha
Hok tốt
\(x^3+\frac{3}{2}x^2+\frac{3}{2}x+\frac{1}{8}\)
\(=\left(x^3+\frac{3}{2}x^2+\frac{3}{4}x+\frac{1}{8}\right)+\frac{3}{2}x-\frac{3}{4}x\)
\(=\left(x+\frac{1}{2}\right)^3+\frac{3}{4}x\)
\(=\left(x+\frac{1}{2}\right)^3+\left(\sqrt[3]{\frac{3}{4}x}\right)^3\)
\(=\left(x+\frac{1}{2}+\sqrt[3]{\frac{3}{4}x}\right)\left[\left(x+\frac{1}{2}\right)^2-\left(x+\frac{1}{2}\right)\left(\sqrt[3]{\frac{3}{4}}\right)+\left(\sqrt[3]{\frac{3}{4}}\right)^2\right]\)
b) \(\frac{2}{3}x^3y^4-\frac{5}{3}x^5y^2\)
\(=x^3y^2\left(\frac{2}{3}y^2-\frac{5}{3}x^2\right)\)
\(=x^3y^2\left(\sqrt{\frac{2}{3}}y+\sqrt{\frac{5}{3}}x\right)\left(\sqrt{\frac{2}{3}}y-\sqrt{\frac{5}{3}}x\right)\)
d) \(x^2-25=\left(x+5\right)\left(x-5\right)\)
2.
pt <=> (x/2000 - 1) + (x+1/2001 - 1) + (x+2/2002 - 1) + (x+3/2003 - 1) + (x+4/2004 - 1 ) = 0
<=> x-2000/2000 + x-2000/2001 + x-2000/2002 + x-2000/2003 + x-2000/2004 = 0
<=> (x-2000).(1/2000 + 1/2001 + 1/2002 + 1/2003 + 1/2004) = 0
<=> x-2000=0 ( vì 1/2000 + 1/2001 + 1/2002 + 1/2003 + 1/2004 > 0 )
<=> x=2000
Tk mk nha
1.
a, = (2x-1)^2-2.(2x-1)+1-4
= (2x-1-1)^2-4
= (2x-2)^2-4
= (2x-2-2).(2x-2+2)
= 2x.(2x-4)
b, = [x.(x+3)].[(x+1).(x+2)]
= (x^2+3x).(x^2+3x+1)-8
= (x^2+3x+1)^2-1-8
= (x^2+3x+1)^2-9
= (x^2+3x+1-3).(x^2+3x+1+3)
= (x^2+3x-2).(x^2+3x+4)
= ((x+1).(x+3).(x^2+3x-2)
Tk mk nha
\(1,\\ a,=4\left(x-2\right)^2+y\left(x-2\right)=\left(4x-8+y\right)\left(x-2\right)\\ b,=3a^2\left(x-y\right)+ab\left(x-y\right)=a\left(3a+b\right)\left(x-y\right)\\ 2,\\ a,=\left(x-y\right)\left[x\left(x-y\right)^2-y-y^2\right]\\ =\left(x-y\right)\left(x^3-2x^2y+xy^2-y-y^2\right)\\ b,=2ax^2\left(x+3\right)+6a\left(x+3\right)\\ =2a\left(x^2+3\right)\left(x+3\right)\\ 3,\\ a,=xy\left(x-y\right)-3\left(x-y\right)=\left(xy-3\right)\left(x-y\right)\\ b,Sửa:3ax^2+3bx^2+ax+bx+5a+5b\\ =3x^2\left(a+b\right)+x\left(a+b\right)+5\left(a+b\right)\\ =\left(3x^2+x+5\right)\left(a+b\right)\\ 4,\\ A=\left(b+3\right)\left(a-b\right)\\ A=\left(1997+3\right)\left(2003-1997\right)=2000\cdot6=12000\\ 5,\\ a,\Leftrightarrow\left(x-2017\right)\left(8x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2017\\x=\dfrac{1}{4}\end{matrix}\right.\\ b,\Leftrightarrow\left(x-1\right)\left(x^2-16\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=4\\x=-4\end{matrix}\right.\)
\(\frac{2}{3}x-\frac{1}{9}x^2-1\)
\(=-\left(\frac{1}{9}x^2-\frac{2}{3}x+1\right)\)
\(=-\left[\left(\frac{1}{3}x\right)^2-2\cdot\frac{1}{3}x\cdot1+1^2\right]\)
\(=-\left(\frac{1}{3}x-1\right)^2\)
\(1,\\ 1,=15\left(x+y\right)\\ 2,=4\left(2x-3y\right)\\ 3,=x\left(y-1\right)\\ 4,=2x\left(2x-3\right)\\ 2,\\ 1,=\left(x+y\right)\left(2-5a\right)\\ 2,=\left(x-5\right)\left(a^2-3\right)\\ 3,=\left(a-b\right)\left(4x+6xy\right)=2x\left(2+3y\right)\left(a-b\right)\\ 4,=\left(x-1\right)\left(3x+5\right)\\ 3,\\ A=13\left(87+12+1\right)=13\cdot100=1300\\ B=\left(x-3\right)\left(2x+y\right)=\left(13-3\right)\left(26+4\right)=10\cdot30=300\\ 4,\\ 1,\Rightarrow\left(x-5\right)\left(x-2\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\\ 2,\Rightarrow\left(x-7\right)\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=7\\x=-2\end{matrix}\right.\\ 3,\Rightarrow\left(3x-1\right)\left(x-4\right)=0\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=4\end{matrix}\right.\\ 4,\Rightarrow\left(2x+3\right)\left(2x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)
\(x^2-\frac{5}{3}x-\frac{2}{3}\)
\(=x^2-2x+\frac{1}{3}x-\frac{2}{3}\)
\(=x\left(x-2\right)+\frac{1}{3}\left(x-2\right)\)
\(=\left(x-2\right)\left(x+\frac{1}{3}\right)\)