xn–1(x + y) – y(xn–1 + yn–1)
Rút gọn biểu thức: xn-1(x + y) – y(xn–1 + yn–1)
x(x – y) + y(x – y)
= x.x – x.y + y.x – y.y
= x2 – xy + xy – y2
= x2 – y2 + (xy – xy)
= x2 – y2
Đề bài: Rút gọn hai biểu thức sau:
a) x(x-y)+y(x-y):
b) xn-1(x+y)-y(xn-1+yn-1).
a: ta có: \(x\left(x-y\right)+y\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y\right)\)
\(=x^2-y^2\)
b: Ta có: \(x^{n-1}\left(x+y\right)-y\left(x^{n-1}+y^{n-1}\right)\)
\(=x^n+x^{n-1}\cdot y-x^{n-1}\cdot y-y^n\)
\(=x^n-y^n\)
rút gọn biểu thức
x(x-y)+y(x-y)
xn-1 (x+y)-y(xn-1+yn-1)
\(x^{n-1}\left(x+y\right)-y\left(x^{n-1}+y^{n-1}\right)\)
=\(x^n+x^{n-1}y-x^{n-1}y-y^n\)
=\(x^n-y^n\)
\(x\left(x-y\right)+y\left(x-y\right)\)
\(=x.x-x.y+y.x-y.y\)
\(=x^2-xy+yx-y^2\)
=\(x^2-y^2\)
x(x-y)+y(x-y)
= x.x+x.(-y)+y.x+y.(-y)
=x^2-xy+yx-y^2
=x^2-y^2
Rút gọn biểu thức:
a) x(x – y) + y(x – y)
b) xn-1(x + y) – y(xn–1 + yn–1)
a) x(x – y) + y(x – y) = x2 – xy + yx – y2 = x2 – xy + xy – y2 = x2 – y2
b) xn–1(x + y) – y( xn–1 + yn–1 ) = xn + xn–1y – yxn–1 – yn
= xn + xn–1y – xn–1y – yn = xn - yn
a) x (x - y) + y (x - y) = x2 – xy+ yx – y2
= x2 – xy+ xy – y2
= x2 – y2
b) xn – 1 (x + y) – y(xn – 1 + yn – 1) =xn+ xn – 1y – yxn – 1 - yn
= xn + xn – 1y - xn – 1y - yn
= xn – yn.
a) x(x – y) + y(x – y) = x2 – xy + yx – y2
= x2 – xy + xy – y2
= x2 – y2
b) xn–1(x + y) – y( xn–1 + yn–1 )
= xn + xn–1y – yxn–1 – yn
= xn + xn–1y – xn–1y – yn
= xn - yn
Bài 4: Làm tính nhân
a) xn. yn+2.(xy+x2y+1)
b) (4xn-2+xn+1).xn
c) 4xy.(xn-2 yn+1+ xn yn+1)
Rút gọn biểu thức x n ( x n + 1 + y n ) - y n ( x n + y n - 1 ) được kết quả là?
A. x 2 n + 1 - y 2 n - 1
B. x 2 n - y 2 n
C. x 2 n - 1 - y 2 n + 1
D. x n + 1 - y n - 1
4xy nhân (xn-2 nhân yn+1+xn nhân yn +1)
4xy nhân (xn-2 nhân yn+1+xn nhân yn+1)
4xy nhân (xn-2 nhân yn+1+xn nhân yn +1)
4x\(^{1+n-2}\)y\(^{1+n+1}\)4xy\(^{1+n}\)+4xy