Khi chia đa thức \(8{x^3}{y^2} - 6{x^2}{y^3}\) cho đơn thức \( - 2xy\) ta được kết quả là
A. \( - 4{x^2}y + 3x{y^2}\)
B. \( - 4x{y^2} + 3{x^2}y\)
C. \( - 10{x^2}y + 4x{y^2}\)
D. \( - 10{x^2}y + 4x{y^2}\)
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Bài 3 :
a )
\(4x^2-4x=0\)
\(\Leftrightarrow4x\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}4x=0\\x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
Vậy \(x=0\) or \(x=1\)
b )
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1.
a.\(4x^2\left(5x^3-3x+1\right)\)
\(=20x^5-12x^3+4x^2\)
b.\(\left(5x^2-4x\right)\left(x-2\right)\)
\(=5x^3-10x^2-4x^2+8x\)
\(=5x^3-14x^2+8x\)
c.\(\left(x^2-2xy+y^2\right)\left(x-y\right)\)
\(=\left(x-y\right)^2\left(x-y\right)\)
\(=\left(x-y\right)^3\)
2.
a.Bạn xem lại đề câu này nhé!
b.\(x^2-y^2-3x-3y\)
\(=\left(x^2-y^2\right)+\left(-3x-3y\right)\)
\(=\left(x+y\right)\left(x-y\right)-3\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-3\right)\)
3.
a.\(4x^2-4x=0\)
\(4x\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}4x=0\\x-1=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
Vậy x=0 hoặc x=1.
1) x^2-1+2xy+y^2 = (x^2+2xy+y^2)-1 = (x+y)^2 - 1^2 = (x+y-1)*(x+y+1)
2) x^4-x^3-x+1 = (x^4-x)-(x^3-1) = x*(x^3-1)-(x^3-1) = (x^3-1)*(x-1)
3) 7x^2-63y^2 = 7*(x^2-9y^2) = 7*[x^2-(3y)^2] = 7*(x-3y)*(x+3y)
còn lại bn tự tính ik nha
Thanks bn nha !
Nhưng mik muốn câu trả lời đầy đủ hơn ạ.
MN GIÚP MIK VS !!!
a) \(-x-y^2+x^2-y\)
\(=\left(x^2-y^2\right)-\left(x+y\right)\)
\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right).1\)
\(=\left(x+y\right)\left(x-y-1\right)\)
b) \(x\left(x+y\right)-5x-5y\)
\(=x\left(x+y\right)-5\left(x+y\right)\)
\(=\left(x+y\right)\left(x-5\right)\)
c) \(x^2-5x+5y-y^2\)
\(=\left(x^2-y^2\right)-5\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y\right)-5\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y-5\right)\)
d) \(5x^3-5x^2y-10x^2+10xy\)
\(=5x\left(x^2-xy-2x+2y\right)\)
\(=5x\left[x\left(x-y\right)-2\left(x-y\right)\right]\)
\(=5x\left(x-y\right)\left(x-2\right)\)
e) \(27x^3-8y^3\)
\(=\left(3x\right)^3-\left(2y\right)^3\)
\(=\left(3x-2y\right)\left[\left(3x\right)^2+3x2y+\left(2y\right)^2\right]\)
\(=\left(3x-2y\right)\left(9x^2+6xy+4y^2\right)\)
f) \(x^2-y^2-x-y\)
\(=\left(x^2-y^2\right)-\left(x+y\right)\)
\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-1\right)\)
g) \(x^2-y^2-2xy+y^2\)
\(=\left(x^2-2xy+y^2\right)-y^2\)
\(=\left(x-y\right)^2-y^2\)
\(=\left(x-y-y\right)\left(x-y+y\right)\)
\(=\left(x-y^2\right)x\)
h) \(x^2-y^2+4-4x\)
\(=\left(x^2-4x+4\right)-y^2\)
\(=\left(x^2-2.2x+2^2\right)-y^2\)
\(=\left(x-2\right)^2-y^2\)
\(=\left(x-2-y\right)\left(x-2+y\right)\)
i) \(x^6-y^6\)
\(=\left(x^3\right)^2-\left(y^3\right)^2\)
\(=\left(x^3-y^3\right)\left(x^3+y^3\right)\)
\(=\left[\left(x-y\right)\left(x^2+xy+y^2\right)\right]\left[\left(x+y\right)\left(x^2-xy+y^2\right)\right]\)
\(=\left(x-y\right)\left(x^2+xy+y^2\right)\left(x+y\right)\left(x^2-xy+y^2\right)\)
\(\dfrac{8x^3y^2-6x^2y^3}{-2xy}=\dfrac{8x^3y^2}{-2xy}+\dfrac{6x^2y^3}{2xy}=-4x^2y+3xy^2\)
⇒ Chọn A.