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1.
\(\frac{25x^4y^3-15x^3y^5+20x^2y^4}{5x^2y^3}\)
\(=\frac{5x^2y^3\left(5x^2-3xy^2+4y\right)}{5x^2y^3}\)
\(=5x^2-3xy^2+4y\)
2.
a) \(27x^4-8x=x\left(27x^3-8\right)\)
\(=x\left(3x-2\right)\left(9x^2+6x+4\right)\)
b) \(16x^2y-4xy^2-4x^3+x^2y\)
\(=4xy\left(4x-y\right)-x^2\left(4x-y\right)\)
\(=x\left(4x-y\right)\left(4y-x\right)\)
c) \(x^2-2x-5+2\sqrt{5}\)
\(=\left(x-1\right)^2-6+2\sqrt{5}\)
\(=\left(x-1\right)^2-\left(6-2\sqrt{5}\right)=\left(x-1\right)^2-\left(\sqrt{5}-1\right)^2\)
\(=\left(x-\sqrt{5}\right)\left(x-2+\sqrt{5}\right)\)
Bài 1:
\(\left(25x^4y^3-15x^3y^5+20x^2y^4\right):\left(5x^2y^3\right)\)
\(=\frac{25x^4y^3-15x^3y^5+20x^2y^4}{5x^2y^3}\)
\(=\frac{5x^2y^3\left(5x^2-3xy^2+4y\right)}{5x^2y^3}\)
\(=5x^2-3xy^2+4y\)
Bài 2:
a) \(27x^4-8x\)
\(=x\left(3x-2\right)\left(3^2x^2+2.3x+2^2\right)\)
\(=x\left(3x-2\right)\left(9x^2+6x+4\right)\)
b) \(16x^2y-4xy^2-4x^3+x^2y\)
\(=4y^2+x^2-\left(4x^2\right)^2\)
\(=x\left(-4x^2+xy+4y^2\right)\)
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Lời giải:
$(4x-2)^2-16x+16x=(4x-2)^2$
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$(3x-4)(3x+4)-(20x^2y-15xy^2):(5xy)$
$=(3x-4)(3x+4)-(4x-3y)$ không phân tích được thành nhân tử.
-----------------------------------
$(x-2)(3x^2+6x+12)-(120^2x^2y^2):(60xy^2)$
$=3(x-2)(x^2+2x+4)-240x$
$=3(x^3-2^3)-240x=3x^3-240x-24$
$=3(x^3-80x-8)$
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Lời giải:
$16x^3y^2-24x^2y^3+20x^4=16x^2(xy^2-\frac{3}{2}y^3+\frac{5}{4}x^2)$
$\Rightarrow 16x^3y^2-24x^2y^3+20x^4\vdots 16x^2$
Đáp án C.
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a) \(4x^3-4x^2=4x^2\left(x-1\right)\)
b) mk chỉnh đề
\(9x^2y^2+15x^2y-21xy^2=3xy\left(3xy+5x-7y\right)\)
c) \(4x^2\left(x-2y\right)-20x\left(2y-x\right)=4x\left(x-2y\right)\left(x+5\right)\)
d) \(4x^2-4x+1=\left(2x-1\right)^2\)
e) bạn ktra lại đề
f) \(16x^2+24xy+9y^2=\left(4x+3y\right)^2\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(5\left(x^2+y^2\right)^2-20x^2y^2\)
\(=5x^4+5y^4-10x^2y^2\)
\(=5\left(x^2-y^2\right)^2\)
\(=5\left(x-y\right)^2\cdot\left(x+y\right)^2\)
Lời giải:
$5(x^2+-y^2)^2-20x^2y^2=5(x^2-y^2)^2-20x^2y^2$
$=5[(x^2-y^2)^2-(2xy)^2]=5(x^2-y^2-2xy)(x^2-y^2+2xy)$
![](https://rs.olm.vn/images/avt/0.png?1311)
\(2x^2+20x-2y^2+50\)
\(\Leftrightarrow2\left(x^2+10x+25-y^2\right)\)
\(\Leftrightarrow2\left[\left(x+5\right)^2-y^2\right]\)
\(\Leftrightarrow2\left(x+5-y\right)\left(x+5-y\right)\)
P/s tham khảo nha
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= ( x3 + 2x2y + xy2 ) - 16x
= x (x2 + 2xy + y2) - 16x
= x( x + y)2 - 16x
= x [ ( x + y)2 - 16 ]
= x ( x + y +4) ( x + y - 4)
lấy 4xy làm nhân tử chung rồi tính nha
hk tốt nha bn