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a) \(9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)
\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)
\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)
\(=\left(-x-3y-5\right)\left(7x+9y-1\right)\)
b) \(3x^4y^2+3x^3y^2+3xy^2+3y^2\)
\(=\left(3x^4y^2+3xy^2\right)+\left(3x^3y^2+3y^2\right)\)
\(=3xy^2\left(x^3+1\right)+3y^2\left(x^3+1\right)\)
\(=\left(3xy^2+3y^2\right)\left(x^3+1\right)\)
\(=3y^2\left(x+1\right)\left(x+1\right)\left(x^2-x+1\right)\)
\(=3y^2\left(x+1\right)^2\left(x^2-x+1\right)\)
c) \(\left(x+y\right)^3-1-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left[\left(x+y\right)^2+x+y+1\right]-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left(x^2+2xy+y^2+x+y+1-3xy\right)\)
\(=\left(x+y-1\right)\left(x^2+x+y^2+y+1-xy\right)\)
a: \(9x^3y^2+3x^2y^2\)
\(=3x^2y^2\cdot3x+3x^2y^2\cdot1\)
\(=3x^2y^2\left(3x+1\right)\)
b: \(x^2-2x+1-y^2\)
\(=\left(x^2-2x+1\right)-y^2\)
\(=\left(x-1\right)^2-y^2\)
\(=\left(x-1-y\right)\left(x-1+y\right)\)
a ) \(\left(3x-1\right)^2+\left(3x+1\right)^2+2\left(3x+1\right)\left(1-3x\right)\)
\(=\left(1-3x\right)^2+\left(3x+1\right)^2+2\left(3x+1\right)\left(1-3x\right)\)
\(=\left(1-3x+3x+1\right)^2\)
\(=2^2=4\)
b ) \(\left(2x-3y\right)^2+\left(2x+3y\right)^2+\left(2x-3y\right)\left(2x+3y\right)\)
\(=4x^2-12xy+9y^2+4x^2+12xy+9y^2+4x^2-9y^2\)
\(=\left(4x^2+4x^2+4x^2\right)+\left(9y^2+9y^2-9y^2\right)+\left(12xy-12xy\right)\)
\(=12x^2+9y^2\)
a,(2x-y)2+(2x+y)2=(2x2-2*2xy+y2)+(2x2+2*2xy+y2)
=2x2-4xy+y2+2x2+4xy+y2
=4x2+2y2
1; \(x^2\) + 3\(x^2\) + 3\(x\) = 4\(x^2\) + 3\(x\) (1)
Thay \(x=99\) vào (1) ta có:
4.992 + 3.99 = 4.9801 + 297 = 39204 + 297 = 39501
\(= ((2x-3y)+(5x+3y))^2-49 = (8x)^2-49 thế x= 1 vào hoặc phân tích tiếp = (8x-7)(8x+7)\)
a. \(\left(2+xy\right)^2=x^2y^2+4xy+4\)
b. \(\left(5-x^2\right)\left(5+x^2\right)=25+5x^2-5x^2-x^4=-x^4+25\)
c. \(\left(2x-y\right)\left(4x^2+2xy+y^2\right)=8x^3+4x^2y+2xy^2-4x^2y-2xy^2-y^3\)
\(=8x^3-y^3\)
d. \(\left(5-3x\right)^2=25-30x+9x^2\)
e. \(\left(5x-1\right)^3=125x^3-75x^3+15x-1\)
f. \(\left(x+3\right)\left(x^2-3x+9\right)=x^3-3x^2+9x+3x^2-9x+27=x^3+27\)
h. \(\left(2x^2+3y\right)^2=4x^4+12x^2y+9y^2\)
a) (2+xy)2 = 22+4xy+(xy)2 = 4 + 4xy +x2y2
b) ( 5 - x^2 ) . ( 5 + x^2 ) = 52-x4=25-x4
c) ( 2x - y ) . ( 4x^2 + 2xy + y^2 ) = 8x3-y3
d)(5-3x)2=52-2.5.3x+9x2=25-30x+9x2
e) (5x-1)3=(5x)3-3.(5x)2.1+3.5x.1-1 =125x3-75x2+15x-1
f) (x+3)(x2-3x+9)=(x+3)(x2-3x+32)=x3+27
g) -x3+3x2-3x+1 =(−x+1)(x−1)(x−1)= -(x-1)3
h) (2x2+3y)2=4x4+2.2x2.3y+9y2=4x4+12x2y+9y2
\(A=9x^2+6xy+y^2-6xy+y^2=9x^2-2y^2\)