Phân tích tử và mẫu thành nhân tử rồi rút gọn phân thức:
a) x2 + xy +x + y / x2 - xy + x - y
b) x2 - 6x+ 9 / 3x2 - 9x
c) y2 - x2 / x2y - xy2
Bài 2:Phân tích đa thức thành nhân tử chung
a, 4(2-x)2+xy-2y
b, x(x-y)3-y(y-x)2-y2(x-y)
c, x2y-xy2-3x+3y
d, x(x+y)2-y(x+y2)+xy-x2
a) \(4\left(2-x\right)^2+xy-2y\)
\(=4\left(x-2\right)^2+\left(xy-2y\right)\)
\(=4\left(x-2\right)\left(x-2\right)+y\left(x-2\right)\)
\(=\left(x-2\right)\left(4x-8\right)+y\left(x-2\right)\)
\(=\left(x-2\right)\left(4x-8+x-2\right)\)
\(=\left(x-2\right)\left(5x-10\right)\)
\(=5\left(x-2\right)^2\)
a, \(=4\left(x-2\right)^2+y\left(x-2\right)=\left(x-2\right)\left(4x-8+y\right)\)
b, \(=x\left(x-y\right)^3-y\left(x-y\right)^2-y^2\left(x-y\right)=\left(x-y\right)\left[x\left(x-y\right)^2-y\left(x-y\right)-y^2\right]=\left(x-y\right)\left[x\left(x^2-2xy+y^2\right)-xy+y^2-y^2\right]=\left(x-y\right)\left(x^3-2x^2y+xy^2-xy\right)=x\left(x-y\right)\left(x^2-2xy+y^2-y\right)\)
c, \(=xy\left(x-y\right)-3\left(x-y\right)=\left(xy-3\right)\left(x-y\right)\)
d, không phân tích được
c, x2y - xy2 - 3x + 3y
= xy(x-y) - 3(x-y)
= (x-y)(x-3)
Phân tích đa thức thành nhân tử:
a) 4 ( 2 - x ) 2 + xy - 2y;
b) x ( x - y ) 3 - y ( y - x ) 2 - y 2 (x - y);
c) x 2 y - xy 2 - 3x + 3y;
d) x ( x + y ) 2 - y ( x + y ) 2 + xy - x 2
Phân tích các đa thức sau thành nhân tử:
a/ x( 3- x) – x + 3 b/ 3x2 – 5x – 3xy + 5y c/ x2 – xy – 10x + 10y
d/ 2xy+ x2 + y2 - 16 e/ x2 – y2 – 4x – 4y f/ 9 – 4x2 + 4xy – y2
g/ y3 – 2xy2 + x2y h/ x3 – 3x2 – 4x + 12 i/ x( x- y) + x2 – y2
a: \(=\left(3-x\right)\left(x+1\right)\)
b: \(=3x\left(x-y\right)-5\left(x-y\right)\)
=(x-y)(3x-5)
c: \(=x\left(x-y\right)-10\left(x-y\right)\)
\(=\left(x-y\right)\left(x-10\right)\)
a) \(=x\left(3-x\right)+\left(3-x\right)=\left(3-x\right)\left(x+3\right)\)
b) \(=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)
c) \(=x\left(x-y\right)-10\left(x-y\right)=\left(x-y\right)\left(x-10\right)\)
d) \(=\left(x+y\right)^2-16=\left(x+y-4\right)\left(x+y+4\right)\)
e) \(=\left(x-y\right)\left(x+y\right)-4\left(x+y\right)=\left(x+y\right)\left(x-y-4\right)\)
f) \(=9-\left(4x^2-4xy+y^2\right)=9-\left(2x-y\right)^2=\left(3-2x+y\right)\left(3+2x-y\right)\)
g) \(=y\left(y^2-2xy+x^2-y\right)\)
h) \(=x^2\left(x-3\right)-4\left(x-3\right)=\left(x-3\right)\left(x^2-4\right)=\left(x-3\right)\left(x-2\right)\left(x+2\right)\)
i) \(=x\left(x-y\right)+\left(x-y\right)\left(x+y\right)=\left(x-y\right)\left(2x+y\right)\)
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
\(a,=5\left(x-y\right)+a\left(x-y\right)=\left(5+a\right)\left(x-y\right)\\ b,=a\left(x+y\right)+b\left(x+y\right)=\left(a+b\right)\left(x+y\right)\\ c,=x\left(x+1\right)+a\left(x+1\right)=\left(x+a\right)\left(x+1\right)\\ d,Sửa:x^2y+xy^2-3x-3y=xy\left(x+y\right)-3\left(x+y\right)=\left(xy-3\right)\left(x+y\right)\\ e,=xy\left(x+1\right)-\left(x+1\right)=\left(xy-1\right)\left(x+1\right)\\ f,=x^2-4=\left(x-2\right)\left(x+2\right)\\ g,=\left(x+3\right)^2-y^2=\left(x-y+3\right)\left(x+y+3\right)\\ h,=\left(x+5\right)^2-y^2=\left(x-y+5\right)\left(x+y+5\right)\\ i,=\left(x-4\right)^2-24y^2=\left(x-2\sqrt{6}y-4\right)\left(x+2\sqrt{6}y+4\right)\)
1. Phân tích thành nhân tử
a) x2 + 7x + 10; b) x2 – 21x + 110; c) 3x2 + 12x + 9; d) 2ax2 - 16ax + 30a.
2. Phân tích thành nhân tử
a) x2 + x – 6; b) x2 – 2x – 15; c) 4x2 - 12x - 160; d) 5x2y - 10xy - 15y.
3. Phân tích thành nhân tử
a) x2 – xy – 20y2 ; b) 3x4 + 6x2y2 – 45y4 ; c) 2bx2 – 4bxy - 70y2
4. Giải phương trình
a) x2 + x = 72; b) 3x2 – 6x = 24 c) 5x3 – 10x2 = 120x.
5. Phân tích thành nhân tử
a) 3x2 -11x + 6; b) 8x2 + 10x – 3 ; c) 8x2 -2x -1 .
Phân tích đa thức thành nhân tử (bằng phương pháp nhóm hạng tử)
c/ 5x2 + 3y + 15x + xy d/ x2 + 6x + 9 – y2
e/ x2 – y2 + 2x + 1 f/ x2 – 2xy – 9 + y2
c) \(5x^2+3y+15x+xy=5x\left(x+3\right)+y\left(x+3\right)=\left(x+3\right)\left(5x+y\right)\)
d) \(x^2+6x+9-y^2=\left(x+3\right)^2-y^2=\left(x+3-y\right)\left(x+3+y\right)\)
e) \(x^2-y^2+2x+1=\left(x^2+2x+1\right)-y^2=\left(x+1\right)^2-y^2=\left(x+1-y\right)\left(x+1+y\right)\)
f) \(x^2-2xy-9+y^2=\left(x^2-2xy+y^2\right)-9=\left(x-y\right)^2-3^2=\left(x-y-3\right)\left(x-y+3\right)\)
c: \(5x^2+15x+3y+xy\)
\(=5x\left(x+3\right)+y\left(x+3\right)\)
\(=\left(x+3\right)\left(5x+y\right)\)
d: \(x^2+6x+9-y^2\)
\(=\left(x+3\right)^2-y^2\)
\(=\left(x+3-y\right)\left(x+3+y\right)\)
e: \(x^2+2x+1-y^2\)
\(=\left(x+1\right)^2-y^2\)
\(=\left(x+1-y\right)\left(x+1+y\right)\)
f: \(x^2-2xy+y^2-9\)
\(=\left(x-y\right)^2-9\)
\(=\left(x-y-3\right)\left(x-y+3\right)\)
Tính:
+ 12x6y3 : 4x3y
+ (x+1)(x2 – x + 1)
+ 2x2y(x2+ 3xy)
Phân tích đa thức thành nhân tử:
+ 4x2y + 6 xy2 -8xy
+x2 – 9
+ x2 – 4 +xy – 2y
+x2 - 7x +10
Tìm x biết:
+x2-x( x-2) = 2
+( x-2)2 + x -2= 0
\(1,\\ 12x^6y^3:4x^3y=3x^3y^2\\ \left(x+1\right)\left(x^2-x+1\right)=x^3+1\\ 2x^2y\left(x^2+3xy\right)=3x^4y+6x^3y^2\\ 2,\\ a,=2xy\left(2x+3y-4\right)\\ b,=\left(x-3\right)\left(x+y\right)\\ c,=\left(x-2\right)\left(x+2\right)+y\left(x-2\right)=\left(x+y+2\right)\left(x-2\right)\\ d,=x^2-2x-5x+10=\left(x-2\right)\left(x-5\right)\\ 3,\\ a,\Leftrightarrow x^2-x^2+2x=2\\ \Leftrightarrow2x=2\Leftrightarrow x=1\\ b,\Leftrightarrow\left(x-2\right)\left(x-2+1\right)=0\\ \Leftrightarrow\left(x-2\right)\left(x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
Phân tích đa thức thành nhân tử
a/ 3x2 – 30x +75
b/ x2 +xy +8x +8y
c/ x2 +4x +4 - y2
a) \(=3\left(x^2-10x+25\right)=3\left(x-5\right)^2\)
b) \(=x\left(x+y\right)+8\left(x+y\right)=\left(x+y\right)\left(x+8\right)\)
c) \(=\left(x+2\right)^2-y^2=\left(x+2-y\right)\left(x+2+y\right)\)
a) =3(x2−10x+25)=3(x−5)2
b) =x(x+y)+8(x+y)=(x+y)(x+8)
c) =(x+2)2−y2=(x+2−y)(x+2+y)
Phân tích các đa thức sau thành nhân tử:
a) x 2 + 6x + 8; b) 2 x 2 + 14x +12;
c) 9 x 2 + 24x +15; d) 6 x 2 -xy-7 y 2 .
a) (x + 2)(x + 4). b) 2(x + 6)(x + l).
c) 3(3x + 5)(x + l). d) (6x -7y)(x + y).