x2+5x-y2-5y
1) x2-x-y2-y
2) x2 -y2 +x-y
3) 3x-3y+x2-y2
4) 5x-5y+x2-y2
5) x2-5x-y2-5y
6) x2-y2 +2x-2y
7) x2 -4y2+x+2y
8) x2-y2-2x-2y
9) x2 -4y2+2x+4y
1: \(x^2-x-y^2-y\)
\(=\left(x^2-y^2\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-1\right)\)
2: \(x^2-y^2+x-y\)
\(=\left(x^2-y^2\right)+\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y\right)+\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y+1\right)\)
3: \(3x-3y+x^2-y^2\)
\(=\left(3x-3y\right)+\left(x^2-y^2\right)\)
\(=3\left(x-y\right)+\left(x-y\right)\left(x+y\right)\)
\(=\left(x-y\right)\left(x+y+3\right)\)
4: \(5x-5y+x^2-y^2\)
\(=\left(5x-5y\right)+\left(x^2-y^2\right)\)
\(=5\left(x-y\right)+\left(x-y\right)\left(x+y\right)\)
\(=\left(x-y\right)\left(5+x+y\right)\)
5: \(x^2-5x-y^2-5y\)
\(=\left(x^2-y^2\right)-\left(5x+5y\right)\)
\(=\left(x-y\right)\left(x+y\right)-5\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-5\right)\)
6: \(x^2-y^2+2x-2y\)
\(=\left(x^2-y^2\right)+\left(2x-2y\right)\)
\(=\left(x-y\right)\left(x+y\right)+2\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y+2\right)\)
7: \(x^2-4y^2+x+2y\)
\(=\left(x^2-4y^2\right)+\left(x+2y\right)\)
\(=\left(x+2y\right)\left(x-2y\right)+\left(x+2y\right)\)
\(=\left(x+2y\right)\left(x-2y+1\right)\)
8: \(x^2-y^2-2x-2y\)
\(=\left(x^2-y^2\right)-\left(2x+2y\right)\)
\(=\left(x-y\right)\left(x+y\right)-2\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-2\right)\)
9: \(x^2-4y^2+2x+4y\)
\(=\left(x^2-4y^2\right)+\left(2x+4y\right)\)
\(=\left(x-2y\right)\left(x+2y\right)+2\left(x+2y\right)\)
\(=\left(x+2y\right)\left(x-2y+2\right)\)
x2 + 5x - 2xy - 5y + y2
\(x^2+5x-2xy-5y+y^2\\ =\left(x^2-2xy+y^2\right)+5x-5y\\ =\left(x-y\right)^2+5\left(x-y\right)\\ =\left(x-y\right)\left(x-y+5\right)\)
\(x^2+5x-2xy-5y+y^2\)
\(=x^2-2xy+y^2+5x-5y\)
\(=\left(x^2-2xy+y^2\right)+5\left(x-y\right)\)
\(=\left(x-y\right)^2+5\left(x-y\right)\)
\(=\left(x-y\right)\left(x-y+5\right)\)
a) x2 - y2 - 2x + 2y b)2x + 2y - x2 - xy
c) 3x2 + 5x - 3xy- 5y d) x2 - 25 + y2 + 2xy
e) x3 - 11 x2 + 30x f) x2 + 3x - 18
phân tích các đa thức thành nhân tử
a) \(=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)=\left(x-y\right)\left(x+y-2\right)\)
b) \(=2\left(x+y\right)-x\left(x+y\right)=\left(x+y\right)\left(2-x\right)\)
c) \(=3x\left(x-y\right)+5\left(x-y\right)=\left(x-y\right)\left(3x+5\right)\)
d) \(=\left(x+y\right)^2-25=\left(x+y-5\right)\left(x+y+5\right)\)
e) \(=x\left(x^2-11x+30\right)\)
f) \(=x\left(x-3\right)+6\left(x-3\right)=\left(x-3\right)\left(x+6\right)\)
phân tích đa thức thành nhân tử
a) x2- x- y2- y
b) x2- 2xy- y2-z2
c) 5x- 5y+ 4x- ay
d) 3x3- x2-21x+ 7
e) x3- 4x2- 8x- 8
f) x3- 5x2- 5x+ 1
g) x2y- xz+ z- y
h) x4- x3+ x2- 1
i) x4- x2+ 10x- 25
a: \(x^2-y^2-x-y\)
\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-1\right)\)
f: \(x^3-5x^2-5x+1\)
\(=\left(x+1\right)\left(x^2-x+1\right)-5x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-6x+1\right)\)
a) x3 - 25x b) x2 – xy - 5x + 5y c) x2 – 3x – 10 d) x2 + 2xy - x - y + y2 - 12
Tìm x,y biết:
3/5x = 2/5y và x2 - y2 = 38
Phân tích đa thức thành nhân tử:
a) x 4 + 1 - 2 x 2 ; b) x 2 - y 2 - 5y + 5x;
c) y 2 - 4 x 2 +4x - 1; d) x3 ( 2 + x ) 2 - ( x + 2 ) 2 + 1 - x 3 .
a) 5x-5y+ax-ay b) ax+ay+bx+by c) x2+x+ax+a
d) x2y+xy2+xy2-3x-3y e) x2y+xy-x-1 f) x2+2x-2x-4
g) x2+6x-y2+9 h) x2-y2+10x+25 i) x2-8x-24y2+16
\(a,=5\left(x-y\right)+a\left(x-y\right)=\left(5+a\right)\left(x-y\right)\\ b,=a\left(x+y\right)+b\left(x+y\right)=\left(a+b\right)\left(x+y\right)\\ c,=x\left(x+1\right)+a\left(x+1\right)=\left(x+a\right)\left(x+1\right)\\ d,Sửa:x^2y+xy^2-3x-3y=xy\left(x+y\right)-3\left(x+y\right)=\left(xy-3\right)\left(x+y\right)\\ e,=xy\left(x+1\right)-\left(x+1\right)=\left(xy-1\right)\left(x+1\right)\\ f,=x^2-4=\left(x-2\right)\left(x+2\right)\\ g,=\left(x+3\right)^2-y^2=\left(x-y+3\right)\left(x+y+3\right)\\ h,=\left(x+5\right)^2-y^2=\left(x-y+5\right)\left(x+y+5\right)\\ i,=\left(x-4\right)^2-24y^2=\left(x-2\sqrt{6}y-4\right)\left(x+2\sqrt{6}y+4\right)\)
Phân tích các đa thức sau thành nhân tử:
a) 2xy + 3z + 6y + xz; b) a 4 - 9 a 3 + a 2 - 9a;
c) 3 x 2 + 5y - 3xy + (-5x); d) x 2 - (a + b)x + ab;
e) 4 x 2 - 4xy + y 2 - 9 t 2 ; g) x 3 – 3 x 2 y + 3x y 2 – y 3 – z 3
h) x2 - y2 + 8x + 6y + 7.
a) Cách 1.
Ta có 2xy + 3z + 6y + xz = (2xy + xz) + (3z + 6y)
= x(2 y + z)+3(z + 2 y) = (z + 2y)(x + 3).
Cách 2.
Ta có 2xy + 3z + 6y + xz = (2x1/ + 6y) + (3z + xz)
= 2y(x + 3) + z(3 + x) = (z + 2y)(x + 3).
b) Biến đổi được a 4 - 9 rt 3 + a 2 -9a = (a- 9)a( a 2 +1).
c) Biến đổi được 3 x 2 + 5y - 3xy + (-5x) = (x - y)(3x - 5).
d) Biến đổi được x 2 - (a + b)x + ab = (x- a)(x - b).
e) Ta có 4 x 2 - 4xy + y 2 – 9 t 2 = ( 2 x - y ) 2 - ( 3 t ) 2
= (2x - y - 3t )(2x - y + 31).
g) Ta có x 3 - 3 x 2 y + 3 xy 2 - y 3 - z 3
= ( x - y ) 3 - z 3 = (x - y - z)( x 2 + y 2 + z 2 - 2xy + xz - yz).
h) Ta có x 2 - y 2 + 8x + 6y+ 7 = ( x 2 +8x + 16) - ( y 2 - 6y+ 9)
= ( x + 4 ) 2 - ( y - 3 ) 2 =(x-y + 7)(x + y + l).