3x^n-2(x^n+2 - y^n+2) +y^n+2(3x^n-2 - y^n-2)
D=3x^n-2.(x^n+2-y^n+2)+y^n+2.(3x^n-2-y^n-2)
D=3xn-2(xn+2-yn+2)+yn+2(3xn-2-yn-2)
= 3xn-2xn-4+2yn-4+yn+6xn-4-2yn-4
= 7xn+yn-16
3x^n-2(x^n+2-y^n+2)+y6n+2(3x^n-2-y^n-2)
\(3x^{n-2}\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\left(3x^{n-2}-y^{n-2}\right)\)
\(3x^{n-2}\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\left(3x^{n-2}-y^{2-2}\right)\)
\(=3x^{2n}-3x^{n-2}y^{n+2}+y^{n+2}\left(3x^{n-2}-y^{n-2}\right)\)
\(=3x^{2n}-3x^{n-2}y^{n+2}+3x^{n-2}y^{n+2}-y^{2n}\)
\(=3x^{2n}-y^{2n}\)
P/s: Mk ko rõ đề nên làm vậy nhé!
Đề bài chắc là đơn giản tỉ lệ thức(rút gọn) nên mình làm luôn nha:
\(3x^{n-2}\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\left(3x^{n-2}-y^{n-2}\right)\)
\(=3x^{2n}-3xy^{2n}+3xy^2-y^{2n}\)
\(=3x^{2n}-y^{2n}\)
1. Thu gọn
a, 3x^n-2 . (x^n+2 -y^n+2 ) + y^n+2 . (3x^n-2 - y^n-2 )
b, 3x^n.(6x^n-3+1)-2x^n . (9x^n-3-1)
c, 5^n+1-4.5^n
d,6x^n : (x^2-1)+2x. (3x^n-1+1)
a) \(=3x^{n-2}.x^{n+2}-3x^{n-2}.y^{n+2}+y^{n+2}.3x^{n-2}-y^{n+2}.y^{n-2}\)
\(=3x^n-y^n\)
b) ; c) ; d) Tương tự nhé
tinh
a)(x-y-z)(x-y)+(y-x-z)(z-x)+(z-x-y)(y-z)
b)3x^n-2(x^n+2-y^n+2)+y^n+2(3x^n-2-y^n-2)
c)(a+b+c)(a^2+b^2+c^2-ab-bc-ca)
b: \(=3x^{n-2+n+2}-3x^{n-2}y^{n+2}+3x^{n-2}y^{n+2}-y^{n+2+n-2}\)
\(=3x^{2n}-y^{2n}\)
c: \(=a^3+ab^2+ac^2-a^2b-abc-a^2c+a^2b+b^3+bc^2-ab^2-b^2c-abc+a^2c+b^2c+c^3-abc-bc^2-ca^2\)
\(=a^3+b^3+c^3-3acb\)
rút gọn: 3xn-2(xn+2-yn+2)+yn+2(3xn-2-yn-2)
Rút gọn các biểu thức sau :
a) \(6x^n\left(x^2-1\right)+2x^3\left(3x^{n+1}+1\right)\)
b) \(3x^{n-2}\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\left(3x^{n-2}-y^{n-2}\right)\)
c) \(x^{n-3}\left(x-y\right)+y\left(x^{n-3}+x^{n-3}y^{n-1}\right)\)
\(3x^{n-2}\cdot\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\cdot\left(3x^{n-2}-y^{n-2}\right)\)=?
thu gọn:
\(3x^{n-2}.\left(x^{n+2}-y^{n+2}\right)+y^{n+2}\left(3x^{n-2}-y^{n-2}\right)\)
\(=3x^{n-2}.x^{n+2}-3x^{n-2}.y^{n+2}+y^{n+2}.3x^{n-2}-y^{n+2}.y^{n-2}\)
\(=3x^{2n}-y^{2n}\)