1) \(12x^2-12xy+3y^2\)
\(=3\left(4x^2-4xy+y^2\right)\)
\(=3\left(2x-y\right)^2\)
5) \(4a^2-x^2-2x-1\)
\(=\left(2a\right)^2-\left(x^2+2x+1\right)\)
\(=\left(2a\right)^2-\left(x+1\right)^2\)
\(=\left(2a-x-1\right)\left(2a+x+1\right)\)
2) \(-12x^4y+12x^3y^2-3x^2y^3\)
\(=-3x^2y\left(y^2-4xy+4x^2\right)\)
\(=-3x^2y\left(y-2x\right)^2\)
3) \(\left(a^2+9\right)^2-36a^2\)
\(=\left(a^2+9\right)^2-\left(6a\right)^2\)
\(=\left(a^2+9+6a\right)\left(a^2+9-6a\right)\)
\(=\left(a+3\right)^2.\left(a-3\right)^2\)
mình không chắc cái này lắm
4) \(x^2+2xy+y^2-25\)
\(=\left(x+y\right)^2-5^2\)
\(=\left(x+y+5\right)\left(x+y-5\right)\)
1) 12x2 - 12xy + 3y2
= 3(4x2 - 4xy + y2)
= 3(2x - 1)2
2) -12x4y + 12x3y2 - 3x2y3
= -3x2y(4x2 + 4xy +y2)
= -3x2y(2x + y)2
3) (a2 + 9)2 - 36a2
= (a2 + 9 + 6a)(a2 + 9 - 6a)
= (a + 3)2(a - 3)2
4) x2 + 2xy + y2 - 25
= (x2 + 2xy + y2) - 25
= (x + y)2 - 25
= ( x + y + 5)(x + y -5)
5) 4a2 - x2 - 2x -1
= 4a2 - (x2+ 2x + 1)
= 4a2 - (x + 1)2
= (2a + x + 1)(2a - x -1)
