P= (x-y)^2 + (x + y)^2 - 2×(x+y) × (x-y)- 4x^2
(4x * y ^ 3)/(x * y ^ 2 - x ^ 2 * y) + (4x ^ 3 * y)/(x ^ 2 * y - x * y ^ 2)
\(\dfrac{4xy^3}{xy^2-x^2y}+\dfrac{4x^3y}{x^2y-xy^2}\)
\(=\dfrac{4xy^3-4x^3y}{xy^2-x^2y}\)
\(=\dfrac{4xy\left(y^2-x^2\right)}{xy\left(y-x\right)}\)
\(=\dfrac{4\left(y-x\right)\left(y+x\right)}{y-x}=4\left(x+y\right)\)
Khi chia đa thức \(8{x^3}{y^2} - 6{x^2}{y^3}\) cho đơn thức \( - 2xy\) ta được kết quả là
A. \( - 4{x^2}y + 3x{y^2}\)
B. \( - 4x{y^2} + 3{x^2}y\)
C. \( - 10{x^2}y + 4x{y^2}\)
D. \( - 10{x^2}y + 4x{y^2}\)
\(\dfrac{8x^3y^2-6x^2y^3}{-2xy}=\dfrac{8x^3y^2}{-2xy}+\dfrac{6x^2y^3}{2xy}=-4x^2y+3xy^2\)
⇒ Chọn A.
D = (x-y / 2y-x - x^2 +y^2 +y-2 / x^2 - xy -2y^2 ) / 4x^4 +4x^2*y +y^2 -4 /x^2 +xy+x+y / x+1 / 2x^2 +y+2
Kb mik nho@ cam on mn nhìu ^.^ :)
Tính giá trị biểu thức :
A=x^2-y^2-4x với x+y=2
B=x^2+y^2+2xy-4x-4y-3 với x+y=4
C=x^3+y^3+3xy(x^2+y^2)+6x^2y^2(x+y) với x+y=1
a) ( x+3 ) * ( x^2 - 3x +9 ) - ( 54+ x^3 )
b) ( 2x + y ) * ( 4x^2 - 2xy + y^2 ) - ( 2x - y ) * ( 4x^2 + 2xy + y^2 )
c) ( a+b ) ^3 - ( a-b ) ^3 - 2b^3
d) ( x+y+z ) ^ 2 - 2 * ( x+y+z ) * ( x+y ) + y^2 + ( x + y ) ^ 2
a) \(\left(x+3\right)\left(x^2-3x+9\right)-\left(54+x^3\right)\)
\(=x^3+27-54-x^3\)
\(=-27\)
b) \(\left(2x+y\right)\left(4x^2-2xy+y^2\right)-\left(2x-y\right)\left(4x^2+2xy+y^2\right)\)
\(=\left(8x^3+y^3\right)-\left(8x^3-y^3\right)\)
\(=8x^3+y^3-8x^3+y^3\)
\(=2y^3\)
c) \(\left(a+b\right)^3-\left(a-b\right)^3-2b^3\)
\(=\left[\left(a+b\right)-\left(a-b\right)\right]\left[\left(a+b\right)^2+\left(a+b\right)\left(a-b\right)-\left(a-b\right)^2\right]-2b^3\)
\(=\left(a+b-a+b\right)\left[\left(a^2+2ab+b^2\right)+\left(a^2-ab+ab-b^2\right)-\left(a^2-2ab+b^2\right)\right]-2b^3\)
\(=b^2\left(a^2+2ab+b^2+a^2-ab+ab-b^2-a^2+2ab-b^2\right)-2b^3\)
....
Rút gọn : \(\left(\frac{x-y}{2y-x}-\frac{x^2+y^2+y-2}{x^2-xy-2y^2}\right):\frac{4x^4+4x^2y+y^2-4}{x^2+xy+x+y}:\frac{x+y}{2x^2+y+2}\)
\(=\left(\dfrac{x-y}{2y-x}-\dfrac{x^2+y^2+y-2}{x^2-2xy+xy-2y^2}\right):\dfrac{\left(2x^2+y\right)^2-4}{x\left(x+y\right)+\left(x+y\right)}:\dfrac{x+y}{2x^2+y+2}\)
\(=\left(\dfrac{x-y}{2y-x}-\dfrac{x^2+y^2+y-2}{\left(x-2y\right)\left(x+y\right)}\right)\cdot\dfrac{\left(x+y\right)\left(x+1\right)}{\left(2x^2+y+2\right)\left(2x^2+y-2\right)}\cdot\dfrac{2x^2+y+2}{x+y}\)
\(=\dfrac{y^2-x^2-x^2-y^2-y+2}{\left(x-2y\right)\left(x+y\right)}\cdot\dfrac{x+1}{2x^2+y-2}\)
\(=\dfrac{-\left(2x^2+y-2\right)}{\left(x-2y\right)\left(x+y\right)}\cdot\dfrac{x+1}{2x^2+y-2}=\dfrac{-\left(x+1\right)}{\left(x-2y\right)\left(x+y\right)}\)
1/ tìm GTNN
4x^2+y^2-4x-2y+3
X^2+y^2+2*(x-2y)y+6
2 phân tich đa thức thành nhân tử
(x+y)^2-25(x+y)+24
2x^3y-2xy-4xy-2xy
y^2 +3xy+3y^2 (y#0)
(x^2+4x+8)^2-3x(x^2+4x+8) +x^2
x^3-y^3-3x+3y
x^4+6x^2+13x^2+12x+4
Rút gọn biểu thức:
a) (x-2)^3-x(x+1)(x-1)+6x(x-3)
b) (2x+y)(4x^2-2xy+y^2)-(2x-y)(4x^2+2xy+y^2)
c) (x+y+z)^2-2(x+y+z)(x+y)+(x+y)
giúp mình vs!!!!
\(a,\left(x-2\right)^3-x\left(x-1\right)\left(x+1\right)+6x\left(x-3\right)\)
\(=x^3-6x^2+12x-27-x^3+x+6x^2-18x\)
\(=-5x-27\)
\(b,\left(2x+y\right)\left(4x^2-2xy+y^2\right)-\left(2x-y\right)\left(4x^2+2xy+y^2\right)\)
\(=8x^3+y^3-\left(8x^3-y^3\right)\)
\(=8x^3+y^3-8x^3+y^3=2y^3\)
\(\left(x+y+z\right)^2-2\left(x+y+z\right)\left(x+y\right)+\left(x+y\right)^2\)
\(=\left(x+y+z-x-y\right)^2\)
\(=z^2\)
a)
=\(x^3-6x^2+12x+8-27-x^3+x+6x^2-18x\)
=-5x-19
b)
=\(8x^3+y^3-8x^3+y^3\)
=\(2y^3\)
c)
=(x+y+z-x-y)\(^2\) +x+y
=\(z^2+x+y\)
hc tốt
Tính giá trị biểu thức :
A=x^2-y^2-4x với x+y=2
B=x^2+y^2+2xy-4x-4y-3 với x+y=4
C=x^3+y^3+3xy(x^2+y^2)+6x^2y^2(x+y) với x+y=1
Tính giá trị biểu thức :
A=x^2-y^2-4x với x+y=2
B=x^2+y^2+2xy-4x-4y-3 với x+y=4
C=x^3+y^3+3xy(x^2+y^2)+6x^2y^2(x+y) với x+y=1
a, \(A=x^2-y^2-4x\)
\(=\left(x^2-y^2\right)-4x\)
\(=\left(x+y\right)\left(x-y\right)-4x\)
\(=2\left(x-y\right)-2.2x\)
\(=2\left(x-y-2x\right)\)
\(=2\left(-x-y\right)\)
\(=2\left[-\left(x+y\right)\right]\)
\(=-2\left(x+y\right)\)
\(=-2.2=-4\)
Vậy \(A=-4\)
b, \(B=x^2+y^2+2xy-4x-4y-3\)
\(=\left(x^2+2xy+y^2\right)-\left(4x+4y\right)-3\)
\(=\left(x+y\right)^2-4\left(x+y\right)-3\)
\(=4^2-4.4-3\)
\(=-3\)
Vậy \(B=-3\)
c, Phần này hình như đề bài sai, bạn xem lại đề hộ mk cái nhé ;)
A =(x+y)(x-y) -4x = 2(x-y) -4x = 2x -2y - 4x = - 2(x+y) = -4
.............