giúp đi các bn
phân tích đa thức thành nhân tử
a, 4y^4 - 1
b, x^2 + 2xy - 9 + y^2
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\(a,Sửa:x^2-xy-13x+13y=x\left(x-y\right)-13\left(x-y\right)=\left(x-13\right)\left(x-y\right)\\ b,=\left(x+y\right)^2-\left(2z\right)^2=\left(x+y-2z\right)\left(x+y+2z\right)\\ c,=\left(x^2-2x\right)-\left(3x-6\right)=x\left(x-2\right)-3\left(x-2\right)=\left(x-2\right)\left(x-3\right)\)
\(x^2-2xy+x-2y=x\left(x-2y\right)+x-2y=\left(x-2y\right)\left(x+1\right)\)
\(3x^3+6x+3-3y^2=3\left[\left(x^2+2x+1\right)-y^2\right]=3\left[\left(x+1\right)^2-y^2\right]=3\left(x-y+1\right)\left(x+y+1\right)\)
a) \(7\left(3x-2\right)+y\left(3x-2\right)=\left(3x-2\right)\left(7+y\right)\)
b) \(x\left(y-x\right)-3\left(x-y\right)=x\left(y-x\right)+3\left(y-x\right)=\left(y-x\right)\left(x+3\right)\)
c) \(x^2-6xy+9y^2=\left(x-3y\right)^2\)
a) x2 - 2xy - 4 + y2
= (x - y)2 - 22
= (x - y - 2)(x - y + 2)
b) x2 + y2 - 1 - 2xy
= (x - y)2 - 12
= (x - y - 1)(x - y + 1)
c) 25 - x2 + 4xy - 4y2
= 52 - (x - 2y)2
= (5 - x + 2y)(5 + x - 2y)
\(4\left(x+3y-4\right)^2-x^2+6x-9\)
\(=\left[2\left(x+3y-4\right)\right]^2-\left(x^2-6x+9\right)\)
\(=\left[2x+6y-8\right]^2-\left(x-3\right)^2\)
\(=\left(2x+6y-8+x-3\right)\left(2x+6y-8-x+3\right)\)
\(=\left(3x+6y-11\right)\left(x+6y-5\right)\)
a) \(7x^2+34x-5=7x\left(x+5\right)-1\left(x+5\right)\)
\(=\left(x+5\right)\left(7x-1\right)\)
b) \(12a^2-3ab+8ac-2bc=3a\left(4a-b\right)+2c\left(4a-b\right)\)
\(=\left(4a-b\right)\left(3a+2c\right)\)
\(a,=7x^2-x+35x-5=x\left(7x-1\right)+5\left(7x-1\right)=\left(x+5\right)\left(7x-1\right)\\ b,=3a\left(4a-b\right)+2c\left(4a-b\right)=\left(3a+2c\right)\left(4a-b\right)\)
\(a,=\left(2y^2-1\right)\left(2y^2+1\right)\\ b,=\left(x+y\right)^2-9=\left(x+y+3\right)\left(x+y-3\right)\)
Lời giải:
a. $4y^4-1=(2y^2)^2-1^2=(2y^2-1)(2y^2+1)$
b. $x^2+2xy-9+y^2=(x^2+2xy+y^2)-9$
$=(x+y)^2-3^2=(x+y-3)(x+y+3)$