Question

[Tiểu Tinh]

Bài1: phân tích đa thức thành nhân tử 

1) 21x^2y - 12xy^2

2) x^3 + x^2 - 2x

3) 3x. (x - 1) + 7x^2. (x - 1)

4) 3x. (x-a) + 4a. (a-x)

5) 1/2x. (x-2) + 4a. (a-x)

6) 21. (x-y)^2 - 7.(y-x)

7) x^2yz + xy^2z^2 + x^2yz^2

8) 9x^2y^2 + 15x^2y - 21xy^2

9) x^2y^2 - 1

10) x^4y^4 - z^4

11) (x+1)^2 - 24

12) (x+1)^2 - (y+6)^2

13) x^6 + 1

14) -4y^2 + 4y - 1

15) (2a + 3)^2 - (2a + 1)^2

Bài2: tìm x, biết:

a) x^4 - 16x =0

b) x. (x-3) - x +3 =0

c) 4x^2 - 1/4 =0

d) x^3 - 3x^2 + 3x - 1=0

e) 8x^3 - 36x^2 + 54x - 27=0

f) x^2 + 4x = -4

g) x^2 = 6x - 9

Giúp mk với, mai mk phải nộp gấp!!

Answer 1

[kudo shinichi]

1)\(21x^2y-12xy^2=xy.\left(21x-12y\right)\)

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

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

15)\(\left(2a+3\right)^2-\left(2a+1\right)^2=\left(2a+3-2a-1\right)\left(2a+3+2a+1\right)=2.\left(4a+4\right)=8\left(a+1\right)\)

14) \(-4y^2+4y-1=-\left[\left(2y\right)^2-2.2y.1+1^2\right]=-\left(2y-1\right)^2\)

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

12) \(\left(x+1\right)^2-\left(y+6\right)^2=\left(x+1-y-6\right)\left(x+1+y+6\right)=\left(x-y-5\right)\left(x+y+7\right)\)

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

Sao nhiều thế!

Answer 2

[Tiểu Tinh]

Đúng là nhiều thật , dù sao cx cảm ơn bn nhìn nha!!!