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a: A=-2xy+xy+xy^2=-xy+xy^2
Bậc là 3
b: \(B=xy^2z+2xy^2z-3xy^2z+xy^2z-xyz=-xyz+xy^2z\)
Bậc là 4
c: \(C=4x^2y^3-x^2y^3+x^4+6x^4-2x^2=3x^2y^3+7x^4-2x^2\)
Bậc là 5
d: \(D=\dfrac{3}{4}xy^2-\dfrac{1}{2}xy^2+xy=\dfrac{1}{4}xy^2+xy\)
bậc là 3
e: \(E=2x^2-4x^2+3z^4-z^4-3y^3+2y^3\)
=-2x^2+2z^4-y^3
Bậc là 4
f: \(=3xy^2z+xy^2z+2xy^2z-4xyz=6xy^2z-4xyz\)
Bậc là 4
a: =(xy-2x)-(y^2-2y)
=x(y-2)-y(y-2)
=(x-y)(y-2)
b: =(x^2-2xy+y^2)-(x-y)
=(x-y)^2-(x-y)
=(x-y)(x-y-1)
c: =(x^2-1)-(2xy-2y)
=(x-1)(x+1)-2y(x-1)
=(x-1)(x+1-2y)
d: =(x+3)(x+3-2x+5)
=(x+3)(8-x)
\(a,xy-2x-y^2+2y\)
\(=x\left(y-2\right)-y\left(y-2\right)\)
\(=\left(x-y\right)\left(y-2\right)\)
\(b,x^2-2xy+y^2-x+y\)
\(=\left(x-y\right)^2-\left(x-y\right)\)
\(=\left(x-y\right)\left(x-y-1\right)\)
\(c,x^2-1-2xy+2y\)
\(=\left(x-1\right)\left(x+1\right)-2y\left(x-1\right)\)
\(=\left(x-1\right)\left(x+1-2y\right)\)
\(d,\left(x+3\right)^2-\left(2x-5\right)\left(x+3\right)\)
\(=\left(x+3\right)\left(x+3-2x+5\right)\)
\(=\left(x+3\right)\left(-x+8\right)\)
#Urushi
\(=\dfrac{x\left(x+y\right)}{\left(x+y\right)\left(x^2+y^2\right)}\cdot\left(\dfrac{1}{x-y}-\dfrac{2xy}{\left(x-y\right)\left(x^2+y^2\right)}\right)\)
\(=\dfrac{x}{x^2+y^2}\cdot\dfrac{x^2+y^2-2xy}{\left(x-y\right)\left(x^2+y^2\right)}\)
\(=\dfrac{x}{x^2+y^2}\cdot\dfrac{x-y}{x^2+y^2}=\dfrac{x\left(x-y\right)}{\left(x^2+y^2\right)^2}\)
\(a,-x^2y-2xy+2x^2y+5xy+2\\ =x^2y+3xy+2\\ b,-2xy+\dfrac{3}{2}xy^2+\dfrac{1}{2}xy^2+xy\\ =-xy+2xy^2\)
\(\left(\frac{1}{3}x+2\right)\left(3x-6\right)\)
\(=\frac{1}{3}x\left(3x-6\right)+2\left(3x-6\right)\)
\(=x^2-2x+6x-12\)
\(=x^2+4x-12\)
\(\left(x^2-3x+9\right)\left(x+3\right)\)
\(=\left(x+3\right)\left(x^2-3x+9\right)\)
\(=x^3+27\)
a) (1/3x+2).(3x-6) = (1/3x.3x)+(1/3x.-6)+(2.3x)+(2.-6) = x^2-2x+6x-12 = x^2+4x-12 = x^2+2x2+2^2-16 = (x+2)^2-16
b) (x^2-3x+9).(x+3) = (x^2.x)+(x^2.3)+(-3x.x)+(-3x.3)+(9.x)+(9.3) = x^3+3x^2-3x^2-9x+9x+27 = x^3+27
c) (-2xy+3).(xy-1) = (-2xy.xy)+(-2xy.-1)+(3.xy)+(3.-1) = -2x^2y^2+2xy+3xy-3 = -2x^2y^2+5xy-3
d) x(xy-1).(xy+1) = (x^2y-x).(xy+1) = (x^2y.xy)+(x^2y.1)+(-x.xy)+(-x.1) = x^3y^2+x^2y-x^2y-x = x^3y^2-x
\(\left(x^2+2xy-3\right).\left(-xy-3\right)\)
\(=-x^3y-3x^2-2x^2y^2-6xy+3xy+9\)
=\(-x^3y-2x^2y^2-3x^2-3xy+9\)
( x2 + 2xy - 3 ) ( - xy - 3 )
= - x3y - 2x2y2 + 3xy - 3x2 - 6xy + 9
= - x3y - 2x2y2 - 3x2 - 3xy + 9