phân tích đa thức thành nhân tử
3 (x+2) + 2x + 4
4 (x-2) - x +2
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3: =4x^2+4x+1-2
=(2x+1)^2-2
\(=\left(2x+1-\sqrt{2}\right)\left(2x+1+\sqrt{2}\right)\)
4: =x^2+xy-5xy-5y^2
=x(x+y)-5y(x+y)
=(x+y)(x-5y)
\(3,x\left(x-1\right)-y\left(1-x\right)=\left(x+y\right)\left(x-1\right)\\ 4,x^3+6x^2y+12xy^2+8y^3=\left(x+2y\right)^3\\ 5,x^2-2xy+y^2-xz+yz=\left(x-y\right)^2-z\left(x-y\right)=\left(x-y-z\right)\left(x-y\right)\\ 6,x^2-y^2-x+y=\left(x-y\right)\left(x+y\right)-\left(x-y\right)=\left(x-y\right)\left(x+y-1\right)\\ 9,x^3+x^2-xy+xy+y^2+y^3\\ =x^2\left(x+1\right)+y^2\left(x+1\right)=\left(x^2+y^2\right)\left(x+1\right)\\ 10,x^2-6\left(x+3\right)-9\\ =x^2-6x-18-9\\ =x^2-6x-27=\left(x-9\right)\left(x+3\right)\)
10: \(x^2-6\left(x+3\right)-9\)
\(=x^2-6x-18-9\)
\(=x^2-6x-27\)
\(=\left(x-9\right)\left(x+3\right)\)
\(1,=x\left(x^2-2x+1-y^2\right)=x\left[\left(x-1\right)^2-y^2\right]=x\left(x-y-1\right)\left(x+y-1\right)\\ 2,=\left(x+y\right)^3\\ 3,=\left(2y-z\right)\left(4x+7y\right)\\ 4,=\left(x+2\right)^2\\ 5,Sửa:x\left(x-2\right)-x+2=0\\ \Leftrightarrow\left(x-2\right)\left(x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
\(x^2-2x+2=\left(x^2-2x+1\right)+1=\left(x-1\right)^2+1\)
Ta có: \(\left(x-1\right)^2\ge0\forall x\)
\(\Rightarrow\left(x-1\right)^2+1\ge1\forall x\)
\(\Rightarrow\left(x-1\right)^2+1>0\forall x\)
\(\Rightarrow\)đa thức \(x^2-2x+2\)vô nghiệm
\(\Rightarrow\)đa thức \(x^2-2x+2\)không phân tích được thành nhân tử
Cái kia tương tự
Tham khảo nhé~
\(x^3+2-2x^2-x=\left(x^3-2x^2\right)-\left(x-2\right)=x^2\left(x-2\right)-\left(x-2\right)=\left(x^2-1\right)\left(x-2\right)=\left(x-1\right)\left(x+1\right)\left(x-2\right)\)
a) x3-2x2-x+2
=x(x2-1)+2(-x2+1)
=x(x2-1)-2(x2-1)
=(x2-1)(x-2)
b)
x2+6x-y2+9
=x2+6x+9-y2
=(x+3)2-y2
=(x+3-y)(x+3+y)
\(3\left(x+2\right)+2x+4=3\left(x+2\right)+2\left(x+2\right)=5\left(x+2\right)\)
\(4\left(x-2\right)-x+2=4\left(x-2\right)-\left(x-2\right)=3\left(x-2\right)\)
\(3\left(x+2\right)+2x+4\)
\(=3\left(x+2\right)+2\left(x+2\right)\)
\(=\left(x+2\right).5\)
\(4\left(x-2\right)-x+2\)
\(=4\left(x-2\right)-\left(x-2\right)\)
\(=3.\left(x-2\right)\)
~ Rất vui vì giúp đc bn ~