a) \(3x^2-3xy-5x+5y\)

\(=\left(3x^2-3xy\right)-\left(5x-5y\right)\)

\(=3x\left(x-y\right)-5\left(x-y\right)\)

\(=\left(x-y\right)\left(3x-5\right)\)

b) \(2x^3y-2xy^3-4xy^2-2xy\)

\(=2xy\left(x^2-y^2-2y-1\right)\)

\(=2xy\left[x^2-\left(y^2+2y+1\right)\right]\)

\(=2xy\left[x^2-\left(y+1\right)^2\right]\)

\(=2xy\left(x-y-1\right)\left(x+y+1\right)\)

c) \(x^2+1+2x-y^2\)

\(=\left(x^2+2x+1\right)-y^2\)

\(=\left(x+1\right)^2-y^2\)

\(=\left(x+1+y\right)\left(x+1-y\right)\)

d) \(x^2+4x-2xy-4y+y^2\)

\(=\left(x^2-2xy+y^2\right)+\left(4x-4y\right)\)

\(=\left(x-y\right)^2+4\left(x-y\right)\)

\(=\left(x-y\right)\left(x-y+4\right)\)

e) \(x^3-2x^2+x\)

\(=x\left(x^2-2x+1\right)\)

\(=x\left(x-1\right)^2\)

f) \(2x^2+4x+2-2y^2\)

\(=2\left(x^2+2x+1-y^2\right)\)

\(=2\left[\left(x^2+2x+1\right)+y^2\right]\)

\(=2\left[\left(x+1\right)^2-y^2\right]\)

\(=2\left(x-y+1\right)\left(x+y+1\right)\)

a: =3x(x-y)-5(x-y)

=(x-y)(3x-5)

b: \(=2xy\left(x^2-y^2-2y-1\right)\)

\(=2xy\left[x^2-\left(y^2+2y+1\right)\right]\)

\(=2xy\left(x-y-1\right)\left(x+y+1\right)\)

d:

Sửa đề: x^2+4x-2xy-4y+y^2

=x^2-2xy+y^2+4x-4y

=(x-y)^2+4(x-y)

=(x-y)(x-y+4)

e: =x(x^2-2x+1)

=x(x-1)^2

f: =2(x^2+2x+1-y^2)

=2[(x+1)^2-y^2]

=2(x+1+y)(x+1-y)

\(=\dfrac{5x^5y^4z}{\dfrac{1}{4}xy^2z}+\dfrac{\dfrac{1}{2}x^4y^2z^3}{\dfrac{1}{4}xy^2z}-\dfrac{2xy^3z^2}{\dfrac{1}{4}xy^2z}\)

=20x^4y^2+2x^3z^2-8yz

a: A=x^2-2xy+y^2+y^2-4y+4+1

=(x-y)^2+(y-2)^2+1>=1
Dấu = xảy ra khi x=y=2

b: B=4x^2+8xy+4y^2+x^2-2x+1+y^2+2y+1-2

=(2x+2y)^2+(x-1)^2+(y+1)^2-2>=-2

Dấu = xảy ra khi x=1 và y=-1

b)x²+2xy+y²-16=(x+y)²-4²=(x+y+4)(x+y-4)

c)3x²+5x-3xy-5y=x(3x+5)-y(3x+5)=(3x+5)(x-y)

d)4x²-6x³y-2x²+8x=2x(2x-3x²y-x+4)

e)x²-4-2xy+y²=(x²-2xy+y²)-4=(x-y)²-2²=(x-y-2)(x-y+2)

k)x²-y²-z²-2yz=x²-(y+z)²=(x-y-z)(x+y+z)

m)6xy+5x-5y-3x²-3y²=3(x²-2xy+y²)+5(x-y)=3(x-y)²+5(x-y)=(x-y)(3x-3y+5)

b. (x^2+2xy+y^2)-16 =(x+y)^2-16=(x+y+4)(x+y-4)

Lâu rồi  hổng thấy ai giải nên giải luôn ak 

Ta có \(5x^2+2xy+2y^2=\left(2x+y\right)^2+\left(x-y\right)^2\ge\left(2x+y\right)^2\Rightarrow\sqrt{5x^2+2xy+2y^2}\ge2x+y.\)

           \(2x^2+2xy+5y^2=\left(x+2y\right)^2+\left(x-y\right)^2\ge\left(x+2y\right)^2\Rightarrow\sqrt{2x^2+2xy+5y^2}\ge x+2y.\)

Suy ra \(Q\ge3\left(x+y\right)=3.1=3\)dấu = xảy ra khi \(\hept{\begin{cases}x+y=1\\x-y=0\end{cases}\Leftrightarrow}x=y=\frac{1}{2}\)

\(a,2x^2-2xy-5x+5y\)

\(=\left(2x^2-2xy\right)-\left(5x-5y\right)\)

\(=2x\left(x-y\right)-5\left(x-y\right)\)

\(=\left(x-y\right)\left(2x-5\right)\)

Xét VT của (1):

\(3VT\)

\(=\sqrt{5x^2+2xy+2y^2}.\sqrt{2^2+2^2+1^2}+\sqrt{2x^2+2xy+5y^2}.\sqrt{2^2+2^2+1^2}\)

\(=\sqrt{\left(x+y\right)^2+4x^2+y^2}.\sqrt{2^2+2^2+1^2}+\sqrt{\left(x+y\right)^2+x^2+4y^2}.\sqrt{2^2+2^2+1^2}\)

\(\ge\left[2\left(x+y\right)+4x+y\right]+\left[2\left(x+y\right)+x+4y\right]=9x+9y\)

\(\Rightarrow VT\ge3x+3y=VT\)

Đẳng thức xảy ra \(\Leftrightarrow...\Leftrightarrow x=y\)

Sau đó thay \(y=x\) vào pt (2) ta được:

\(\sqrt{3x+1}+2\sqrt[3]{19x+8}=2x^2+x+5\)

\(\Leftrightarrow\left(2x^2-\sqrt{3x+1}\right)+\left(x-5-2\sqrt[3]{19x+8}\right)=0\)

\(\Leftrightarrow\dfrac{4x^2-3x-1}{2x^2+\sqrt{3x+1}}+\dfrac{\left(x+5\right)^3-8\left(19x+8\right)}{\left(x-5\right)^2+2\left(x-5\right)\sqrt[3]{19x+8}+4\sqrt[3]{\left(19x+8\right)^2}}=0\)

\(\Leftrightarrow\dfrac{\left(x-1\right)\left(4x+1\right)}{2x^2+\sqrt{3x+1}}+\dfrac{ \left(x-1\right)\left(x^2+16x-61\right)}{\left(x-5\right)^2+2\left(x-5\right)\sqrt[3]{19x+8}+4\sqrt[3]{\left(19x+8\right)^2}}=0\)

\(\Leftrightarrow\left(x-1\right)\left[\dfrac{4x+1}{2x^2+\sqrt{3x+1}}+\dfrac{x^2+16x-61}{\left(x-5\right)^2+2\left(x-5\right)\sqrt[3]{19x+8}+4\sqrt[3]{\left(19x+8\right)^2}}\right]=0\)

\(\Leftrightarrow x=1\Rightarrow y=1\)