Khai triển tích: (3x^2y^3+z)^3 Help
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\left(3x^2-2y\right)^3=27x^6-54x^4y+36x^2y^2-8y^3\)
a) \(\left(2x^3-y^2\right)^3\)
\(=\left(2x^3\right)^3-3\cdot\left(2x^3\right)^2\cdot y^2+3\cdot2x^3\cdot\left(y^2\right)^{^2}-\left(y^2\right)^3\)
\(=8x^9-3\cdot4x^6y^2+3\cdot2x^3y^4-y^6\)
\(=8x^9-12x^6y^2+6x^3y^4-y^6\)
b) \(\left(x-3y\right)\left(x^2+3xy+9y^2\right)\)
\(=x^3-\left(3y\right)^3\)
\(=x^3-27y^3\)
c) \(\left(x+2y+z\right)\left(x+2y-z\right)\)
\(=\left(x+2y\right)^2-z^2\)
\(=x^2+4xy+4y^2-z^2\)
d) \(\left(2x^3y-0,5x^2\right)^3\)
\(=\left(2x^3y-\dfrac{1}{2}x^2\right)^3\)
\(=8x^9y^3-6x^8y^2+\dfrac{3}{2}x^7y-\dfrac{1}{8}x^6\)
e) \(\left(x^2-3\right)\left(x^4+3x^2+9\right)\)
\(=\left(x^2-3\right)\left(4x^2+9\right)\)
\(=4x^4+9x^2-12x^2-27\)
\(=4x^4-3x^2-27\)
f) \(\left(2x-1\right)\left(4x^2+2x+1\right)\)
\(=\left(2x\right)^3-1^3\)
\(=8x^3-1\)
\(a,\left(2x^3-y^2\right)^3=8x^9-12x^6y^2+6x^3y^4-y^6\)\(b,\left(x-3y\right)\left(x^2+3xy+9y^2\right)=x^3-27y^3\)
\(c,\left(x+2y+z\right)\left(x+2y-z\right)=\left(x+2y\right)^2-z^2=x^2+4xy+4y^2-z^2\)\(d,\left(2x^3y-0,5x^2\right)^3=8x^9y^3-6x^4y^2x^2+3x^3yx^4-0,125x^6=8x^9y^3-6x^6y^2+3x^7y-0,125x^6\)
a) \(\begin{array}{l}{(x - 3)^4} = {x^4} + 4{x^3}.( - 3) + 6{x^2}.{( - 3)^2} + 4x.{( - 3)^3} + {( - 3)^4}\\ = {x^4} - 12{x^3} + 54{x^2} - 108x + 81\end{array}\)
b) \({(3x - 2y)^4} = 81{x^4} - 216{x^3}y + 216{x^2}{y^2} - 96x{y^3} + 16{y^4}\)
c)
\(\begin{array}{l}{(x + 5)^4} + {(x - 5)^4} = {x^4} + 20{x^3} + 150{x^2} + 500x + 625\\ + {x^4} - 20{x^3} + 150{x^2} - 500x + 625\\ = 2{x^4} + 300{x^2} + 1250\end{array}\)
d) \({(x - 2y)^5} = {x^5} - 10{x^4}y + 40{x^3}{y^2} - 80{x^2}{y^3} + 80x{y^4} - 32{y^5}\)
\(\left(3x-2y\right)^3=\left(3x\right)^3-3.\left(3x\right)^2.2y+3.3x.\left(2y\right)^2-\left(2y\right)^3\)
\(=27x^3-54x^2y+36xy^2-8y^3\)
5:
a: (2x-5)(2x+5)=4x^2-25
b: (3x-5y)(3x+5y)=9x^2-25y^2
c: (3x+7y)(3x-7y)=9x^2-49y^2
d: (2x-1)(2x+1)=4x^2-1
4:
a: 2003*2005=(2004-1)(2004+1)=2004^2-1<2004^2
b: 8(7^2+1)(7^4+1)(7^8+1)
=1/6*(7-1)(7+1)(7^2+1)(7^4+1)(7^8+1)
=1/6(7^2-1)(7^2+1)(7^4+1)(7^8+1)
=1/6(7^16-1)<7^16-1
5:
a: (2x-5)(2x+5)=4x^2-25
b: (3x-5y)(3x+5y)=9x^2-25y^2
c: (3x+7y)(3x-7y)=9x^2-49y^2
d: (2x-1)(2x+1)=4x^2-1
mik chỉ biết bài 5 thôi !
\(\left(3x^2y^3+z\right)^3=27x^6y^9+27x^4y^6z+9x^2y^3z^3+z^3\)