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4 tháng 8 2020

a/ \(3x^2-5x-2\)

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

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

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

b/ \(2x^2+x-6\)

\(=2x^2+4x-3x-6\)

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

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

c/ \(7x^2+50x+7\)

\(=7x^2+49x+x+7\)

\(=7x\left(x+7\right)+\left(x+7\right)\)

\(=\left(x+7\right)\left(7x+1\right)\)

d/ \(12x^2+7x-12\)

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

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

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

e/ \(15x^2+7x-2\)

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

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

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

f/ \(a^2-5a-14\)

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

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

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

g/ \(2m^2+10m+8\)

\(=2m^2+2m+8m+8\)

\(=2m\left(m+1\right)+8\left(m+1\right)\)

\(=\left(m+1\right)\left(2m+8\right)\)

h/ \(4p^2-36p+56\)

\(=4p^2-28p-8p+56\)

\(=4p\left(p-7\right)-8\left(p-7\right)\)

\(=\left(p-7\right)\left(4p-8\right)\)

29 tháng 7 2022

câu i) tách 5x sao vậy ạ ?

 

19 tháng 8 2019
https://i.imgur.com/pcpV5iA.jpg
15 tháng 9 2017

f)\(x^2-5x-14=x^2-7x+2x-14=x\left(x-7\right)+2\left(x-7\right)=\left(x-7\right)\left(x+2\right)\)

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

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

g)\(x^2+6x+5=x^2+x+5x+5=x\left(x+1\right)+5\left(x+1\right)=\left(x+1\right)\left(x+5\right)\)

15 tháng 9 2017

f)\(x^2-5x-14=x^2-7x+2x-14\)

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

i)\(x^2-7x+10=x^2-5x-2x+10\)

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

h)\(x^2-7x+12=x^2-4x-3x+12\)

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

g)\(x^2+6x+5=x^2+x+5x+5\)

                           \(=\left(x+5\right)\left(x+1\right)\)

                             

1 tháng 7 2019

2x^2 + x - 6

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

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

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

7x^2 + 50x + 7 

= 7x^2 + x + 49x + 7

= 7x(x + 7) + x + 7

= (7x + 1)(x + 7)

12x^2 + 7x - 12

15x^2 +  7x - 2

= 15x^2 - 3x + 10x - 2

= 3x(5x - 1) + 2(5x - 1) 

= (3x + 2)(5x - 1)

a^2 - 5a - 14

= a^2 + 2a - 7a - 14

= a(a + 2) - 7(a + 2)

= (a - 7)(a + 2)

2x^2 + 5x + 2

= 2x^2 + x + 4x + 2

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

= (2x + 1)(x + 2)

\(2x^2+x-6=2x^2+4x-3x-6\)

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

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

\(7x^2+50x+7\)

\(=7x^2+x+49x+7\)

\(=x\left(7x+1\right)+7\left(7x+1\right)\)

\(=\left(7x+1\right)\left(x+7\right)\)

\(12x^2+7x-12\)

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

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

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

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

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

4 tháng 8 2020

Bài 1 : Phân tích các đa thức sau thành nhân tử : ( tách một hạn tử thành nhiều hạng tử )
a, 3x2 + 9x - 30

= 3(x2 + 3x - 10)

= 3(x2 + 5x - 2x - 10)

= 3[x(x + 5) - 2(x + 5)]

= 3(x + 5)(x - 2)

b, x2 - 3x + 2

= x2 - x - 2x + 2

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

= (x - 1)(x - 2)
c, x2 - 9x + 18

= x2 - 6x - 3x + 18

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

= (x - 6)(x - 3)
d, x2 - 6x + 8

= x2 - 4x - 2x + 8

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

= (x - 4)(x - 2)
e, x2 - 5x - 14

= x2 + 2x - 7x - 14

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

= (x + 2)(x - 7)
f, x2 + 6x + 5

= x2 + x + 5x + 5

= x(x + 1) + 5(x + 1)

= (x + 1)(x + 5)
h, x2 - 7x + 12

= x2 - 3x - 4x + 12

= x(x - 3) - 4(x - 3)

= (x - 3)(x - 4)
i, x2 - 7x + 10

= x2 - 2x - 5x + 10

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

= (x - 2)(x - 5)

#Học tốt!

21 tháng 8 2021

Phân tích đa thức thành nhân tử(tách hạng tử)
1)x^2+2x-3=x^2-x+3x-3=x(x-1)+3(x-1)=(x-1)(x+3)
2)x^2-5x+6=x^2-2x-3x+6=x(x-2)-3(x-2)=(x-2)(x-3)
3)x^2+7x+12=(x+3)(x+4)
4)x^2-x-12=(x-4)(x+3)
5)3x^2+3x-36=3[(x-3)(x+4)]
6)5x^2-5x-10=5[(x-2)(x+1) ]       
7)3x^2-7x-6=(x-3)(3x+2)
8)4x^2+4x-3=4x^2+6x-2x-3=(2x-1)(2x+3)
9)8x^2-2x-3=8x^2+4x-6x-3=(4x-3)(2x+1)
 

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

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

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

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

5: \(3x^2+3x-36=3\left(x^2+x-12\right)=3\left(x+4\right)\left(x-3\right)\)

6: \(5x^2-5x-10=5\left(x^2-x-2\right)=5\left(x-2\right)\left(x+1\right)\)