\(=3\left[\left(x+y\right)^2-2xy\right]-\left[\left(x+y\right)^3-3xy\left(x+y\right)\right]+1\)
\(=3\left(2^2-2xy\right)-\left(2^3-3xy\cdot2\right)+1\)
\(=12-6xy-8+6xy+1=5\)
tinh gt cac bieu thuc sau :
a, A=(x^2y+y^3) (x^2+y^2)-y(x^4+y^4)
b,B=(2x-y) (2x+y)-100
voi x=-25 , y=10
B=[1/x^2 + 1/y^2 + 2/x+y.( 1/x + 1/y )] : x^3+y^3/x^2.y^2
thực hiện phép tính
a,\(x^3+\left[\frac{x\left(2y^3-x^3\right)}{x^3+y^3}\right]^3-\left[\frac{y\left(2x^3-y^3\right)}{x^3+y^3}\right]^3\)
b,\(\frac{\frac{x\left(x+y\right)}{x-y}+\frac{x\left(x+z\right)}{x-z}}{1+\frac{\left(y-z\right)^2}{\left(x-y\right)\left(x-z\right)}}+\frac{\frac{y\left(y+z\right)}{y-z}+\frac{y\left(y+x\right)}{y-x}}{1+\frac{\left(z-x\right)^2}{\left(y-z\right)\left(y-x\right)}}+\frac{\frac{z\left(z+x\right)}{z-x}+\frac{z\left(z+y\right)}{z-y}}{1+\frac{\left(x-y\right)^2}{\left(z-x\right)\left(z-y\right)}}\)
c,\(\left[\frac{y+z-2x}{\frac{\left(y-z\right)^3}{y^3-z^3}+\frac{\left(x-y\right)\left(x-z\right)}{y^2+yz+z^2}}+\frac{z+x-2y}{\frac{\left(z-x\right)^3}{z^3-x^3}+\frac{\left(y-z\right)\left(y-x\right)}{z^2+xz+x^2}}+\frac{x+y-2z}{\frac{\left(x-y\right)^3}{x^3-y^3}+\frac{\left(z-x\right)\left(z-y\right)}{x^2+xy+y^2}}\right]:\frac{1}{x+y+z}\)
chứng minh hằng đẳng thức:
1, \(\left(x^2-xy+y^2\right)\left(x+y\right)=x^3+y^3\)
2, \(x^2-y^2=\left(x-y\right)\left(x+y\right)\)
3, \(x^2+2x+1=\left(x+1\right)^2\)
4,\(x^3-y^3=(x-y)(x^2+xy+y^2)\)
Thực hiện phép tính: 1) 4x3y2 : x2 2) (3x2 - 6x) : (2 - x). 3) (x3 - 8) : (x2 + 2x + 4) 4) (3x2 - 6x):(2-x) 5) (x3 + 2x2-2x-1):(x2+3+1) 6) [5(x-y)4-3(x-y)3+4(x-y)2]:(x-y)2 7) [(x-y)5-2(x+y)4+3(x+3)3]:(x+y)3 8) (x2-2xy+y2):(x-y) 9) (27x3+1):(9x2-3x+1)
Tính GT biểu thức
a, A= 2. (X^3 + y^3) - 3(x^2+y^2) biết x+y=1
b, x^3 + y^3 + 3xy biết x+y=1
Cho x, Y, z khác 0 thỏa mãn (x-y-z) ^2=x^2+y^2+z^2 Cm 1/x^3 -1/y^3 -1/z^3=3/xyz
1. Cho x + y + 5 và x2 + y2 = 15. Tính x3- y
2. Cho x+ y= 4. Tính
A= x2 + y2 + 2xy - 4x - 4y - 3
3. Cho x + y = 1. Tính
A= 2.( x3 + y3 ) - 3. ( x2 + y2 )
4. Cho x3 + y2 = 1. Tính A= 2x6 + 3x3 y3+ y6 + y3
Giúp mk mai mk nộp rùi
giải phương trình nghiệm nguyên
a)2x^2+y^2-2xy+4x-4y=0
b)x^2+x=y^4+y^3+y^2+y
c)1+x+x^2+x^3+x^4=y^4
d)x^3+7y=y^3+7x (x,y thuộc N*)
