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26 tháng 7 2021

a, \(x^2-5x+6=x^2+x-6x+6=x\left(x-1\right)-6\left(x-1\right)=\left(x-1\right)\left(x-6\right)\)

b, \(3x^2+9x-30=3\left(x^2+3x-10\right)=3\left(x^2-2x+5x-10\right)\)

\(=3\left[x\left(x-2\right)+5\left(x-2\right)\right]=3\left(x-2\right)\left(x+5\right)\)

c, \(x^2+7x+10=x^2+2x+5x+10=x\left(x+2\right)+5\left(x+2\right)=\left(x+2\right)\left(x+5\right)\)

26 tháng 7 2021

a) x2 - 5x + 6 = (x2-2x)-(3x-6)=x(x-2)-3(x-2)=(x-3)(x-2)

b) 3x2 + 9x -30= 3(x2+3x-10) = 3((x2+5x)-(2x+10)) = 3(x(x+5)-2(x+5)) = 3(x-2)(x+5)

c) x2 + 7x + 10 =( x2+5x)+(2x+10)=x(x+5)+2(x+5)=(x+2)(x+5)

6 tháng 9 2020

a) \(x^2-5x+6=x^2-2x-3x+6=\left(x-2\right)\left(x-3\right)\)

b)\(3x^2+9x-30=3x^2-6x+15x-30=3\left(x-2\right)\left(x+5\right)\)

c)\(x^2-7x+12=x^2-3x-4x+12=\left(x-3\right)\left(x-4\right)\)

d)\(x^2-7x+10=x^2-2x-5x+10=\left(x-2\right)\left(x-5\right)\)

6 tháng 9 2020

a) \(x^2-5x+6=x^2-2x-3x+6=\left(x^2-2x\right)-\left(3x-6\right)\)

\(=x\left(x-2\right)-3\left(x-2\right)=\left(x-2\right)\left(x-3\right)\)

b) \(3x^2+9x-30=3\left(x^2+3x-10\right)=3\left(x^2-2x+5x-10\right)\)

\(=3\left[\left(x^2-2x\right)+\left(5x-10\right)\right]=3\left[x\left(x-2\right)+5\left(x-2\right)\right]\)

\(=3\left(x-2\right)\left(x+5\right)\)

c) \(x^2-7x+12=x^2-3x-4x+12=\left(x^2-3x\right)-\left(4x-12\right)\)

\(=x\left(x-3\right)-4\left(x-3\right)=\left(x-3\right)\left(x-4\right)\)

d) \(x^2-7x+10=x^2-2x-5x+10=\left(x^2-2x\right)-\left(5x-10\right)\)

\(=x\left(x-2\right)-5\left(x-2\right)=\left(x-2\right)\left(x-5\right)\)

24 tháng 10 2018

a) x2 - 5x + 6

= x2 - 2x - 3x + 6

=(x2 - 2x) - (3x + 6)

=x.(x - 2) - 3.(x - 2)

=(x-2).(x-3)

b) 3x2+9x-30

=3x2+15x-6x-30

=(3x2+15x) - (6x+30)

= 3x(x+5) - 6(x+5)

=(x+5).(3x-6)

c) x2-3x+2

=x2-2x-x+2

=(x2-2x) - (x-2)

=x(x-2)-(x-2)

=(x-2)(x-1)

24 tháng 10 2018

a)x- 5x + 6

= x- 2x - 3x + 6

=x.(x - 2) - 3(x - 2)

=(x - 2).(x - 3)

b)3x+9x -30

=3x+15x - 6x -30

=3x.(x+5) - 6.(x + 5)

=(x+5).(3x - 6)

c)x- 3x +2

=x- 2x - x +2

=x.(x- 2) - 1.(x-2)

=(x-2).(x - 1)

d)x- 9x +18

=x- 6x -3x +18

=x.(x - 6) -3.(x - 6)

=(x - 6).(x - 3)

e)x- 6x +8

=x- 2x - 4x +8

=x.(x - 2)- 4.(x - 2)

=(x - 2).(x - 4)

f)x- 5x -14

=x+ 2x - 7x - 14

=x.(x + 2) -7.(x + 2)

=(x + 2).(x - 7)

9 tháng 9 2017

a) \(x^4-9x^2\)

\(=x^2\left(x^2-9\right)\)

\(=x^2\left(x-3\right)\left(^{ }x+3\right)\)

b) \(3x^2-12x+12\)

\(=3x\left(x^2-4x+4\right)\)

\(=3x\left(x-2\right)^2\)

c) \(x^2+5x+6\)

\(=x^2+3x+2x+6\)

\(=x\left(x+3\right)+2\left(x+3\right)\)

\(=\left(x+3\right)\left(x+2\right)\)

x4 - 9x2

= x4 - ( 3x )2

= ( x2 - 3x ) ( x2 + 3x )

b) 3x3 - 12x2 + 12x

= 3x3 - 6x- 6x2 + 12x

= 3x2( x - 2 ) - 6x ( x - 2 )

= ( 3x2 - 6x ) ( x - 2 )

= 3x ( x - 2 ) ( x - 2 )

= 3x ( x- 2 )2

c) x2 + 5x + 6

= x2 + 2x + 3x + 6

= x ( x + 2 ) + 3 ( x + 2 )

= ( x + 3 ) ( x + 2 )

22 tháng 8 2016

a) \(x^2\)\(-5x+6\)

=\(x^2\)\(-3x-2x+6\)

=\(x\left(x-3\right)-2\left(x-3\right)\)

=\(\left(x-2\right)\left(x-3\right)\)

b) \(3x^2\)\(+9x-30\)

=\(3x^2\)\(-6x+15x-30\)

=\(3x\left(x-2\right)+15\left(x-2\right)\)

=\(\left(x-2\right)\left(3x+15\right)\)

c)\(x^2\)\(-3x+2\)

=\(x^2\)\(-2x-x+2\)

=\(x\left(x-2\right)-\left(x-2\right)\)

=\(\left(x-2\right)\left(x-1\right)\)

d) \(12x^2\)\(+7x-12\)

=\(12x^2\)\(-9x+16x-12\)

=\(3x\left(4x-3\right)+4\left(4x-3\right)\)

=\(\left(3x+4\right)\left(4x-3\right)\)

e) \(15x^2\)\(+7x-2\)

=\(15x^2\)\(-3x+10x-2\)

=\(3x\left(5x-1\right)+2\left(5x-1\right)\)

=\(\left(3x+2\right)\left(5x-1\right)\)

f) \(a^2\)\(-5a-14\)

=\(a^2\)\(-7a+2a-14\)

=\(a\left(a-7\right)+2\left(a-7\right)\)

=\(\left(a+2\right)\left(a-7\right)\)

g) \(x^2\)\(-\left(a+b\right)x+ab\)

=\(x^2\)\(-ax-bx+ab\)

=\(x\left(x-a\right)-b\left(x-a\right)\)

=\(\left(x-a\right)\left(x-b\right)\)

 

4 tháng 8 2017

Mình sửa: Bài 1
2)x2+3x-15

20 tháng 5 2018

a) x2 + 6x + 9 = x2 + 2 . x . 3 + 32 = (x + 3)2

b) 10x – 25 – x2 = -(-10x + 25 +x2) = -(25 – 10x + x2)

                         = -(52 – 2 . 5 . x – x2) = -(5 – x)2

c) 8x3 - 1/8 = (2x)3 – (1/2)3 = (2x - 1/2)[(2x)2 + 2x . 12 + (1/2)2]

                    = (2x - 1/2)(4x2 + x + 1/4) 

d)1/25x2 – 64y2 = (1/5x)2(1/5x)2- (8y)2 = (1/5x + 8y)(1/5x - 8y)

16 tháng 10 2016

\(2x^2+3x-27=2x^2-6x+9x-27=2x\left(x-3\right)+9\left(x-3\right)=\left(2x+9\right)\left(x-3\right)\)

\(x^3-7x+6=x^3-x-6x+6=x\left(x^2-1\right)-6\left(x-1\right)=x\left(x-1\right)\left(x+1\right)-6\left(x-1\right)=\left(x-1\right)\left(x^2+x-6\right)\)

\(x^3+5x^2+8x+4=x^3+x^2+4x^2+8x+4=x^2\left(x+1\right)+4\left(x^2+2x+1\right)=x^2\left(x+1\right)+4\left(x+1\right)^2\)

\(=\left(x+1\right)\left(x^2+4x+4\right)=\left(x+1\right)\left(x+2\right)^2\)

\(27x^3-27x^2+18x-4=27x^3-9x^2-18x^2+6x+12x-4\)

\(=9x^2\left(3x-1\right)-6x\left(3x-1\right)+4\left(3x-1\right)=\left(3x-1\right)\left(9x^2-6x+4\right)\)

28 tháng 6 2016

a)x2+5x-6

=x2+6x-x-6

=x(x+6)-(x+6)

=(x-1)(x+6)

b)7x-6x2-2

=-6x2+3x+4x-2

=-3x(2x-1)+2(2x-1)

=(2x-1)(-3x+2)

c)x2+4x+3

=x2+3x+x+3

=x(x+3)+(x+3)

=(x+1)(x+3)

d)2x2+3x-5

=2x2+5x-2x-5

=x(2x+5)-(2x+5)

=(x-1)(2x+5)

7 tháng 10 2017

a x2 - 7x - 6 = x2 -6x-x-6

= x(x-6)+(x-6)

= (x+1)(x+6)

b x3 + 4x2 - 7x -10

=x3 - 2x2 + 6x-12x+5x-10

= x2(x-2) + 6x(x-2) + 5(x-2)

= (x2 +6x+5)(x-2)

=(x2 +x+5x+5)(x-2)

=[x(x+1)+5(x+1)](x-2)

=(x+5)(x+1)(x-2)

c x3 +x2-2

=x3-x2+2x2-2x+2x-2

=x2(x-1)+2x(x-1)+2(x-1)

=(x2+2x+2)(x-1)

d x2 +5x+6

=x2 +2x+3x+6

=x(x+2)+3(x+2)

=(x+3)(x-2)

Con 1 y e nhung luoi lam

3 tháng 9 2018

mk chỉnh lại đề

\(x^2-7x+6\)

\(=x^2-x-6x+6\)

\(=x\left(x-1\right)-6\left(x-1\right)\)

\(=\left(x-1\right)\left(x-6\right)\)