a) 3x^4 - 12x^2 = 3x^2.(x^2 - 4) = 3x^2.(x - 2)(x + 2)

b) x^2 - 2xy + 3x - 6y

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

= (x - 2y)(x + 3) 

a) 3x^4 - 12x^2

= 3x^2.x^2- 3.4x^2

= x^2-4

b) x ^2 - 2xy + 3x - 6y

=(x^2-2xy) +(3x-6y)

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

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

tự làm đi

bạn ơi  bạn viết sai đề có đề nào viết  thế này đâu?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

Uchiha Itachi

Trả lời:

a, x⁴ + 3x³ + x² + 3x

= ( x⁴ + 3x³ ) + ( x² + 3x )

= x³ ( x + 3 ) + x ( x + 3 )

= ( x³ + x ) ( x + 3 )

= x ( x² + 1 ) ( x + 3 )

b, Sửa đề: x⁴ - x² + 8x - 8

= ( x⁴ - x² ) + ( 8x - 8 )

= x² ( x² - 1 ) + 8 ( x - 1 ) 

= x² ( x - 1 ) ( x + 1 ) + 8 ( x - 1 )

= ( x - 1 ) [ x² ( x + 1 ) + 8 ]

= ( x - 1 ) ( x³ + x² + 8 )

x⁴ + 3x³ + x² + 3x = x³(x + 3) + x(x + 3)
= (x + 3)(x² + 1)x

Trả lời:

5, x² - y² + 4x + 4 

= ( x² + 4x + 4 ) - y²

= ( x + 2 )² - y²

= ( x + 2 - y ) ( x + 2 + y )

6, x² + 2x - 4y² - 4y

= ( x² - 4y² ) + ( 2x - 4y )

= ( x - 2y ) ( x + 2y ) + 2 ( x - 2y )

= ( x - 2y ) ( x + 2y + 2 )

7, 3x² - 4y + 4x - 3y²

= ( 3x² - 3y² ) + ( 4x - 4y )

= 3 ( x² - y² ) + 4 ( x - y )

= 3 ( x - y ) ( x + y ) + 4 ( x - y )

= ( x - y ) [ 3 ( x + y ) + 4 ]

= ( x - y ) ( 3x + 3y + 4 )

8, x⁴ - 6x³ + 54x - 81

= ( x⁴ - 81 ) - ( 6x³ - 54x )

= ( x² - 9 ) ( x² + 9 ) - 6x ( x² - 9 )

= ( x² - 9 ) ( x² + 9 - 6x )

= ( x - 3 ) ( x + 3 ) ( x - 3 )²

= ( x - 3 )³ ( x + 3 )

a, \(x^2-y^2+4x+4=\left(x+2\right)^2-y^2=\left(x+2-y\right)\left(x+2+y\right)\)

b, \(x^2+2x-4y^2-4y=\left(x-2y\right)\left(x+2y\right)+2\left(x-2y\right)=\left(x-2y\right)\left(x+2+2y\right)\)

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

d, \(x^4-6x^3+54x-81=\left(x^2+9\right)\left(x-3\right)\left(x+3\right)-6x\left(x^2-9\right)\)

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

5, x²-y²+4x+4

=(x²+4x+4)-y²

=(x+2)²-y²

=(x+2-y)(x+2+y)

6, x²+2x-4y²-4y

=(x²-4y²)+(2x-4y)

=(x-2y)(x+2y)+2(x-2y)

=(x-2y)(x+2y+2)

7, 3x²-4y+4x-3y²

=(3x²-3y²)+(4x-4y)

=3(x²-y²)+4(x-y)

=3(x-y)(x+y)+4(x-y)

=(x-y)[3(x+y)+4]

=(x-y)(3x+3y+4)

8, x⁴-6x³+54x-81

=(x⁴-81)-(6x³-54x)

=(x²-9)(x²+9)-6x(x²-9)

=(x²-9)(x²+9-6x)

=(x+3)(x-3)(x-3)²

=(x+3)(x-3)³

#H

7,      4x mũ 2 - 12x + 9 - y mũ 2 =  -(y-2x+3) (y+2x-3)

8,      16x mũ 2 - 4y mũ 2 + 4y - 1 =   -(2y - 4x - 1) (2y+4x-1)

9,        25 - x mũ 2 - 12x - 36 =  -(x+1) (x+11)

10,        x mũ 2 - 9 - 5 ( x + 3 ) =  (x-8) (x+3)

bạn k cho mình nha 

chúc bạn học tốt :))))

bạn kham khảo link, mình đã làm rồi nhé

Câu hỏi của Phạm Đỗ Bảo Ngọc - Toán lớp 8 - Học trực tuyến OLM 

Trả lời:

7, 4x² - 12x + 9 - y²

= ( 4x² - 12x + 9 ) - y² 

= ( 2x - 3 )² - y² 

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

8, 16x² - 4y² + 4y - 1

= 16x² - ( 4y² - 4y + 1 )

= ( 4x )² - ( 2y - 1 )²

= ( 4x - 2y + 1 )( 4x + 2y - 1 )

9, 25 - x² - 12x - 36

= 25 - ( x² + 12x + 36 )

= 5² - ( x + 6 )²

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

= ( - 1 - x )( 11 + x )

10, x² - 9 - 5 ( x + 3 )

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

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

= ( x + 3 )( x - 8 )

a, \(x^2-4-3\left(x-2\right)=\left(x-2\right)\left(x+2\right)-3\left(x-2\right)=\left(x-1\right)\left(x-2\right)\)

b, \(x^2-xy+5y-25=\left(x-5\right)\left(x+5\right)-y\left(x-5\right)=\left(x+5-y\right)\left(x-5\right)\)

c, \(x^3+x^2-2x-8=\left(x-2\right)\left(x^2+2x+4\right)+x\left(x-2\right)=\left(x-2\right)\left(x^2+3x+4\right)\)

d, \(x^3-4x^2-8x+8=\left(x+2\right)\left(x^2-2x+4\right)-4x\left(x+2\right)=\left(x^2-6x+4\right)\left(x+2\right)\)

Trả lời:

1, x² - 4 - 3 ( x - 2 )

= ( x² - 4 ) - 3 ( x - 2 )

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

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

= ( x - 2 ) ( x - 1 )

2, x² - xy + 5y - 25

= ( x² - 25 ) - ( xy - 5y )

= ( x - 5 ) ( x + 5 ) - y ( x - 5 )

= ( x - 5 ) ( x + 5 - y )

3, x³ + x² - 2x - 8

= ( x³ - 8 ) + ( x² - 2x )

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

= ( x - 2 ) ( x² + 2x + 4 + x )

= ( x - 2 ) ( x² + 3x + 4 )

4, x³ - 4x² - 8x + 8 

= ( x³ + 8 ) - ( 4x² + 8x )

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

= ( x + 2 ) ( x² - 2x + 4 - 4x )

= ( x + 2 ) ( x² - 6x + 4 )

xin lỗi em lớp 3 :>>>>

𝑥2−3𝑥+2

(x-5)^2

k nhé tó k lại

.....me chịu.

KHông thì. bạn tải qanda nhé.

chụp bài rồi gửi ,người ta giải cho .

nhưng nó ko quét bài viết bài tay đâu nhé,chỉ quét chữ in thôi.