Rút gọn các biểu thức sau
xong nhanh trong ngày tui tích :D
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
`1)(a^[1/4]-b^[1/4])(a^[1/4]+b^[1/4])(a^[1/2]+b^[1/2])`
`=[(a^[1/4])^2-(b^[1/4])^2](a^[1/2]+b^[1/2])`
`=(a^[1/2]-b^[1/2])(a^[1/2]+b^[1/2])`
`=a-b`
`2)(a^[1/3]-b^[2/3])(a^[2/3]+a^[1/3]b^[2/3]+b^[4/3])`
`=(a^[1/3]-b^[2/3])[(a^[1/3])^2+a^[1/3]b^[2/3]+(b^[2/3])^2]`
`=(a^[1/3])^3-(b^[2/3])^3`
`=a-b^2`
a: Ta có: \(\left(x+y\right)^2+\left(x-y\right)^2-2x^2\)
\(=x^2+2xy+y^2+x^2-2xy+y^2-2x^2\)
\(=2y^2\)
b: Ta có: \(\left(x+1\right)^3-\left(x-1\right)\left(x^2+x+1\right)-3x\left(x+1\right)\)
\(=x^3+3x^2+3x+1-x^3+1-3x^2-3x\)
=2
9x - 7i > 3 . \((3x-7u)\)
=> 9x - 71 > 9x - 21u
=> -7i > -21u
=> 7i < 21u
=> i < 3u
9x - 7i > 3 (3x - 7u)
9x-7i>9x-21u
-7i>-21u
i<3u
a:
ĐKXĐ: x>=0; x<>1
Sửa đề: \(M=x-\dfrac{2x-2\sqrt{x}}{\sqrt{x}-1}+\dfrac{x\sqrt{x}+1}{x-\sqrt{x}+1}+1\)
\(=x-\dfrac{2\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}-1}+\dfrac{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}{x-\sqrt{x}+1}+1\)
\(=x-2\sqrt{x}+1+\sqrt{x}+1=x-\sqrt{x}+2\)
b: \(M=x-\sqrt{x}+2\)
\(=x-\sqrt{x}+\dfrac{1}{4}+\dfrac{7}{4}\)
\(=\left(\sqrt{x}-\dfrac{1}{2}\right)^2+\dfrac{7}{4}>=\dfrac{7}{4}\forall x\) thỏa mãn ĐKXĐ
Dấu '=' xảy ra khi \(\sqrt{x}-\dfrac{1}{2}=0\)
=>\(\sqrt{x}=\dfrac{1}{2}\)
=>x=1/4
a) \(=x^2+2x-2x=x^2\)
b) \(=4-x^2+x^2=4\)
c) \(=x^2-x^3+x^3+27=x^2+27\)
d) \(=4x^2+4xy+y^2+4x^2-8x^2-4xy=y^2\)
a, \(A=\left(x-1\right)\left(x^2+x+1\right)-\left(x+1\right)\left(x^2-x+1\right)=x^3-1-x^3-1=-2\)
b, \(B=2x\left(4x+1\right)-8x^2\left(x+1\right)+\left(2x\right)^3-2x+3\)
\(=8x^2+2x-8x^3-8x^2+8x^3-2x+3=3\)
c, \(C=\left(x-1\right)^3+\left(x+1\right)^3+2x\left(x+2\right)\left(x-2\right)\)
\(=\left(x-1+x+1\right)^3-3\left(x-1\right)\left(x+1\right)\left(x-1+x+1\right)+2x\left(x^2-4\right)\)
\(=8x^3-6x\left(x^2-1\right)+2x^3-8x=8x^3-6x^3+6x+2x^3-8x=4x^3-2\)
d, \(D=\left(x+y-5\right)^2-2\left(x+y-5\right)\left(x+3\right)+x^2+6x+9\)
\(=\left(x+y-5-x-3\right)^2=\left(y-8\right)^2=y^2-16x+64\)