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\(x^3-3x^2+3x-1-y^3\)
\(=\left(x-1\right)^3-y^3\)
\(=\left(x-1-y\right)\left[\left(x-1\right)^2+y\left(x-1\right)+y^2\right]\)
\(=\left(x-y-1\right)\left[\left(x-1\right)\left(x-1+y\right)+y^2\right]\)
\(x^3-3x^2+3x-1-y^3\)
\(=\left(x-1\right)^3-y^3\)
\(=\left(x-1-y\right)\left[\left(x-1\right)^2+y\left(x-1\right)+y^2\right]\)
\(=\left(x-y-1\right)\left[\left(x-1\right)\left(x-1+y\right)+y^2\right]\)
Rất vui vì giúp đc bạn <3
\(x^3-3x^2+3x-1-y^3\)
\(=\left(x-1\right)^3-y^3\)
\(=\left(x-1-y\right)\left[\left(x-1\right)^2+y\left(x-1\right)+y^2\right]\)
\(=\left(x-y-1\right)\left[\left(x-1\right)\left(x-1+y\right)+y^2\right]\)
\(x^3-3x^2+3x-1-y^3\\ =\left(x-1\right)^3-y^3\\ =\left(x-1-y\right)\text{[ (x-1)^2+y(x-1)+y^2}\)
\(=\left(x-y-1\right)\left[\left(x-1\right)\left(x-1+y\right)+y^2\right]\)
Đặt \(x^2-3x-1=a\)thay vào biểu thức ta được :
\(a^2-12a+27\)
\(=a^2-3a-9a+27\)
\(=a\left(a-3\right)-9\left(a-3\right)\)
\(=\left(a-3\right)\left(a-9\right)\)(1)
Thay \(a=x^2-3x-1\)vào (1) ta được :
\(\left(x^2-3x-1-3\right)\left(x^2-3x-1-10\right)\)
\(=\left(x^2-3x-4\right)\left(x^2-3x-11\right)\)
Bạn Châu sai đáp án cuối
phải là (x2-3x-4)(x2-3x-10) nha
\(x^3+3x^2+3x+1=x^3+3x^2.1+3x.1^2+1^3\)
\(=\left(x+1\right)^3\)
\(x^3+3x^2+3x+1\)
\(=\left(x^3+1\right)+\left(3x^2+3x\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)+3x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-x+1+3x\right)\)
\(=\left(x+1\right)\left(x^2+2x+1\right)\)
\(=\left(x+1\right)\left(x+1\right)^2\)
\(=\left(x+1\right)^3\)
(Nhớ k cho mình với nha!)
\(\left(x^2+3x+1\right)\left(x^2+3x+2\right)-6\)
Đặt \(x^2+3x+1=a,\)ta được:
\(a\left(a+1\right)-6\)
\(=a^2+a-6=\left(a^2+3a\right)-\left(2a+6\right)\)
\(=a\left(a+3\right)-2\left(a+3\right)=\left(a+3\right)\left(a-2\right)\)
Thay \(a=x^2+3x+1,\)ta được:
\(\left(x^2+3x+1+3\right)\left(x^2+3x+1-2\right)\)\(=\left(x^2+3x+4\right)\left(x^2+3x-1\right)\)
Ta có : (x3 + 3x + 1)(x3 + 3x + 2) - 6
= (x3 + 3x + 1,5 - 0,5)(x3 + 3x + 1,5 + 0,5) - 6
= (x3 + 3x + 1,5)2 - 0,52 - 6
= (x3 + 3x + 1,5)2 - 6,25
= (x3 + 3x + 1,5 - 2,5) (x3 + 3x + 1,5 + 2,5)
= (x3 + 3x - 1) (x3 + 3x + 3)
x3 + 3x2y - 9xy2 + 5y3
= ( x3 - 3x2y + 3xy2 - y3 ) + ( 6y3 - 12xy2 + 6 x2y )
= ( x - y )3 + 6y ( x - y )2
= ( x - y )2 ( x + 5y )
\(x^3-3x^2+1-3x\)
\(=\left(x^3+1\right)-\left(3x^2+3x\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)-3x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-x+1-3x\right)\)
\(=\left(x+1\right)\left(x^2-4x+1\right)\)
Chúc bạn học tốt.
\(x^3-3x^2+1-3x\)
\(=\left(x^3+1\right)-3x^2-3x\)
\(=\left(x+1\right)\left(x^2-x+1\right)-3\left(x^2+1\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)-3\left(x+1\right)\left(x+1\right)\)
\(=\left(x+1\right)\left[x^2-x+1-3\left(x+1\right)\right]\)
\(=\left(x+1\right)\left(x^2-x+1-3x-3\right)\)
\(=\left(x+1\right)\left(x^2-4x-2\right)\)