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Y
1
26 tháng 7 2016
a) = (x-3)(x+3) +(x-3((x-3)
= (x-3)(x+3+x-3)
= 2x(x-3)
làm cho 1 câu thui
VR
2
16 tháng 7 2015
b) \(x^3-4x^2-12x+27=\left(x^3+27\right)-\left(4x^2+12x\right)\)
\(=\left(x+3\right)\left(x^2-3x+9\right)-4x\left(x+3\right)\)
\(=\left(x+3\right)\left(x^2-3x+9-4x\right)\)
\(=\left(x+3\right)\left(x^2-7x+9\right)\)
16 tháng 5 2017
d) \(x^{16}-1=\left(x^4-1\right)\left(x^4+1\right)=\left(x^2-1\right)\left(x^2+1\right)\left(x^4+1\right)\)
Y
4
27 tháng 7 2016
\(x^3+2x^2+x-4xy^2\)
\(=x\left(x^2+2x+1\right)-4xy^2\)
\(=x\left(x+1\right)^2-4xy^2\)
\(=x\left(\left(x+1\right)^2-4y^2\right)\)
\(=x\left(\left(x+1-2y\right)\left(x+1+2y\right)\right)\)
27 tháng 7 2016
\(\text{x3+2x2+x−4xy2 =x(x2+2x+1)−4xy2 =x(x+1)2−4xy2 =x((x+1)2−4y2) =x((x+1−2y)(x+1+2y))}\)
12 tháng 8 2016
a) x3 - x2 - 5x + 125
=(x3-6x2+25x)+(5x2-30x+125)
=x(x2-6x+25)+5(x2-6x+25)
=(x+5)(x2-6x+25)
b) x3 + 2x2 - 6x - 27
=x3+5x2+9-3x2-15x-27
=x(x2+5x+9)-3(x2+5x+9)
=(x-3)(x2+5x+9)
c) 12x3 + 4x2 - 27x - 9
=4x2(3x+1)-9(3x+1)
=(4x2-9)(3x+1)
=[(2x)2-32](3x+1)
=(2x-3)(2x+3)(3x+1)
12 tháng 8 2016
a) \(x^3-x^2-5x+125\)
\(=\left(x^3+125\right)-\left(x^2+5x\right)\)
\(=\left(x+5\right)\left(x^2-5x+25\right)-x\left(x+5\right)\)
\(=\left(x+5\right)\left(x^2-5x+25-x\right)=\left(x+5\right)\left(x^2-6x+25\right)\)
b) \(x^3+2x^2-6x-27\)
\(=\left(x^3-27\right)+\left(2x^2-6x\right)\)
\(=\left(x-3\right)\left(x^2+3x+9\right)+2x\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2+3x+9+2x\right)\)
\(=\left(x-3\right)\left(x^2+5x+9\right)\)
c) \(12x^3+4x^2-27x-9\)
\(=4x^2\left(3x+1\right)-9\left(3x+1\right)\)
\(=\left(3x-1\right)\left(4x^2-9\right)=\left(3x-1\right)\left(2x-3\right)\left(2x+3\right)\)
NT
1
24 tháng 10 2016
a) \(4x^2-8x+4-9\left(x-y\right)^2\)
\(=4\left(x^2-2x+1\right)-9\left(x-y\right)^2\)
\(=\left[2\left(x-1\right)\right]^2-\left[3\left(x-y\right)\right]^2\)
\(=\left(2x-2+3x-3y\right)\left(2x-2-3x+3y\right)\)
\(=\left(5x-3y-2\right)\left(3y-x-2\right)\)
b) \(x^3-4x^2+12x-27\)
\(=\left(x^3-27\right)-\left(4x^2-12x\right)\)
\(=\left(x-3\right)\left(x^2+3x+9\right)-4x\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2-x+9\right)\)
9 tháng 10 2018
a, 4x2 - 12x + 9
= (2x + 3)2
b, 9x4y3 + 3x2y4
= 3x2y3(3x2 + y)
c, ( x - 3 )2 - 2x ( x - 3 )
= (x - 3)(x - 3 - 2x)
= (x - 3)(-x - 3)
d, 3x ( x - 1 ) + 6 ( x - 1 )
= 3(x - 1)(x + 2)
e, 2x ( x + 1 ) - 4x - 4
= 2x(x + 1) - 4(x + 1)
= (x + 1)(2x - 4)
= 2(x + 1)(x - 2)
f, ( 2x - 3 )2 - 4x + 6
= (2x - 3)2 - 2(2x - 3)
= (2x - 3)(2x - 3 - 2)
= (2x - 3)(2x - 5)
TM
20 tháng 11 2016
a) \(\left(x+8\right)^2-2\left(x+8\right)\left(x-2\right)+\left(x-2\right)^2\)
\(=\left[\left(x+8\right)-\left(x-2\right)\right]^2\)
\(=\left(x+8-x+2\right)^2\)
\(=10^2\)
\(=2^2.5^2\)
b)\(x^3-4x^2-12x+27=\left(x^3+27\right)-\left(4x^2+12x\right)\)
\(=\left(x+3\right)\left(x^2-3x+9\right)-4x\left(x+3\right)\)
\(=\left(x+3\right)\left(x^2-3x+9-4x\right)\)
\(=\left(x+3\right)\left(x^2-7x+9\right)\)
c)\(x^3+6x^2+11x+6=x^3+x^2+5x^2+5x+6x+6\)
\(=x^2\left(x+1\right)+5x\left(x+1\right)+6\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2+5x+6\right)\)
\(=\left(x+1\right)\left(x^2+2x+3x+6\right)\)
\(=\left(x+1\right)\left[x\left(x+2\right)+3\left(x+2\right)\right]\)
\(=\left(x+1\right)\left(x+2\right)\left(x+3\right)\)
d)\(x^3+6x^2-13x-42=x^3-3x^2+9x^2-27x+14x-42\)
\(=x^2\left(x-3\right)+9x\left(x-3\right)+14\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2+9x+14\right)\)
\(=\left(x-3\right)\left(x^2+2x+7x+14\right)\)
\(=\left(x-3\right)\left[x\left(x+2\right)+7\left(x+2\right)\right]\)
\(=\left(x-3\right)\left(x+2\right)\left(x+7\right)\)
11 tháng 10 2017
b)3x^2-18x+27=3x^2-9x-9x+27=3x*(x-3)-9*(x-3)=(x-3)*(3x-9)=(x-3)*3*(x-3)=3*(x-3)^2
c)x^3-4x^2-12x+27=(x+3)*(x^2-3x+9-4)=(x+3)*(x^2-3x+5)
d)27x^3-1/27=(3x-1/3)*(9x^2-x+1/9) (hang dt)
con a) voi e) mk chiu
14 tháng 8 2015
a) x^2 - 4 + ( x - 2 )^2
= ( x- 2 )(x + 2 ) + ( x- 2)^2
= ( x - 2 ) ( x + 2 + x - 2 )
= 2x (x-2)
b) x^3 - 2x^2 + x - xy^2
= x ( x^2 - 2x + 1 - y^2)
= x [ ( x - 1 )^2 - y^2 ]
= x(x - 1 - y)( x - 1 + y )
c) x^3 - 4x^2 - 12x + 27
= x^3 + 3x^2 - 7x^2 - 21x + 9x + 27
= x^2 ( x + 3 ) - 7x ( x+ 3 ) + 9(x + 3 )
Để hai lần nha
= ( x+ 3 )(x^2 - 7x + 9 )
30 tháng 9 2018
\(x^2-4+\left(x-2\right)^2\)
\(=\left(x-2\right)\left(x+2\right)+\left(x-2\right)^2\)
\(=\left(x-2\right)\left(x+2+x-2\right)\)
\(=2x\left(x-2\right)\)
hk tốt
^^
a/ = (x2 - 9) + (x - 3)2
= (x - 3)(x + 3) + (x - 3)2
= (x - 3)(x + 3 + x - 3)
= 2x(x - 3)
b/ = x3 - 7x2 + 9x + 3x2 - 21x + 27
= x(x2 - 7x + 9) + 3(x2 - 7x + 9)
= (x + 3)(x2 - 7x + 9)
c/ = x2 - 3x + 6x - 18
= x(x - 3) + 6(x - 3)
= (x + 6)(x - 3)