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a/ \(=x^3-2x^5\)

b/\(=5x^2+5-x^3-x\)

c/ \(=x^3+3x^2-4x-2x^2-6x+8=x^3=x^2-10x+8\)

d/ \(=x^2-x^3+4x-2x+2x^2-8=3x^2-x^3+2x-8\)

e/ \(=x^4-x^2+2x^3-2x\)

f/ \(=\left(6x^2+x-2\right)\left(3-x\right)=17x^2+5x-6-6x^3\)

Dễ

 Thế

Mà

Cũnhoir

Dc

Ạ

Chịu

Chắc

Phải

Ngu 

Lamqs

Mới

Hỏi

Câu

Này

Bài 5: 

a. 1 - 2y + y²

= (1 - y)²

b. (x + 1)² - 25

= (x + 1)² - 5²

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

= (x - 4)(x + 6)

c. 1 - 4x²

= 1² - (2x)²

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

d. 8 - 27x³

= 2³ - (3x)³

= (2 - 3x)(4 + 6x + 9x²)

e. (đề hơi khó hiểu ''x3'' !?)

g. x³ + 8y³

= (x + 2y)(x² - 2xy + y²)

Giúp mk vs

a: \(=x^3-2x^5\)

e: \(=x^4+2x^3-x^2-2x\)

a)=\(3x^3-15x^2+21x\)

b)\(=-2x^4y-10x^2y+2xy\)

c)\(=-x^3+6x^2+5x-4x^2+24x+20=-x^3+2x^2+29x+20\)

d)\(=2x^4-3x^3+4x^2-2x^2+3x-4=2x^4-3x^32x^2+3x-4\)

e)\(=x^2-4y^2\)

f)\(=-2x^2y^3+y-3\)

g)\(=3xy^4-\dfrac{1}{2}y^2+2x^2y\)

h)\(=9x^2-6x+1-7x^2-14=2x^2-6x-13\)

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

j)\(=\left(x+2y\right)\left(x^2-2y+4y^2\right):\left(x+2y\right)=x^2-2y+4y^2\)

Bài 1. Tính:

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

\(=x^3-2x^5\)

b) \(\left(x^2+1\right)\left(5-x\right)\)

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

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

\(=x^3+3x^2-4x-2x^2-6x+8\)

\(=x^3+x^2-10x+8\)

d) \(\left(x-2\right)\left(x-x^2+4\right)\)

\(=x^2-x^3+4x-2x+2x^2-8\)

\(=3x^2-x^3+2x-8\)

e) \(\left(x^2-1\right)\left(x^2+2x\right)\)

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

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

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

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

\(=18x^2+3x-6-6x^3-x^2+2x\)

\(=17x^2+5x-6-6x^3\)

g) \(\left(x+3\right)\left(x^2+3x-5\right)\)

\(=x^3+3x^2-5x+3x^2+9x-15\)

\(=x^3+6x^2+4x-15\)

h) \(\left(xy-2\right)\left(x^3-2x-6\right)\)

\(=x^4y-2x^2y-6xy-2x^3+4x+12\)

i) \(\left(5x^3-x^2+2x-3\right)\left(4x^2-x+2\right)\)

\(=20x^3-5x^4+10x^3-4x^4+x^3-2x^2+8x^3-2x^2+4x-12x^2+3x-6\)

\(=39x^3-9x^4-16x^2+7x-6\)

Bài 5: Tìm x, biết

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

\(\Leftrightarrow\left(x^2-4x+4\right)-\left(x^2-9\right)-6=0\)

\(\Leftrightarrow x^2-4x+4-x^2+9-6=0\)

\(\Leftrightarrow-4x+7=0\)

\(\Leftrightarrow-4x=-7\)

\(\Leftrightarrow x=\dfrac{-7}{-4}=\dfrac{7}{4}\)

Vậy \(x=\dfrac{7}{4}\)

2) \(4\left(x-3\right)^2-\left(2x-1\right)\left(2x+1\right)=10\)

\(\Leftrightarrow4\left(x^2-6x+9\right)-\left(4x^2-1\right)-10=0\)

\(\Leftrightarrow4x^2-24x+36-4x^2+1-10=0\)

\(\Leftrightarrow-24x+27=0\)

\(\Leftrightarrow-24x=-27\)

\(\Leftrightarrow x=\dfrac{-27}{-24}=\dfrac{9}{8}\)

Vậy \(x=\dfrac{9}{8}\)

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

\(\Leftrightarrow\left(x^2-8x+16\right)-\left(x^2-4\right)-6=0\)

\(\Leftrightarrow x^2-8x+16-x^2+4-6=0\)

\(\Leftrightarrow-8x+14=0\)

\(\Leftrightarrow-8x=-14\)

\(\Leftrightarrow x=\dfrac{-14}{-8}=\dfrac{7}{4}\)

Vậy \(x=\dfrac{7}{4}\)

5) \(9\left(x+1\right)^2-\left(3x-2\right)\left(3x+2\right)=10\)

\(\Leftrightarrow9\left(x^2+2x+1\right)-\left(9x^2-4\right)-10=0\)

\(\Leftrightarrow9x^2+18x+9-9x^2+4-10=0\)

\(\Leftrightarrow18x+3=0\)

\(\Leftrightarrow18x=-3\)

\(\Leftrightarrow x=\dfrac{-3}{18}=\dfrac{-1}{6}\)

Vậy \(x=\dfrac{-1}{6}\)

Bài 8: Phân tích đa thức thành nhân tử

1) \(5x^2-10xy+5y^2-20z^2\)

\(=5\left(x^2-2xy+y^2-4z^2\right)\)

\(=5\left[\left(x^2-2xy+y^2\right)-4z^2\right]\)

\(=5\left[\left(x-y\right)^2-\left(2z\right)^2\right]\)

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

2 \(16x-5x^2-3\)

\(=-5x^2+16x-3\)

\(=-5x^2+15x+x-3\)

\(=-\left(5x^2-15x\right)+\left(x-3\right)\)

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

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

3) \(x^2-5x+5y-y^2\)

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

\(=\left(x-y\right)\left(x+y\right)-5\left(x-y\right)\)

\(=\left(x-y\right)\left(x+y-5\right)\)

4) \(3x^2-6xy+3y^2-12z^2\)

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

\(=3\left[\left(x^2-2xy+y^2\right)-4z^2\right]\)

\(=3\left[\left(x-y\right)^2-\left(2z\right)^2\right]\)

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

5) \(x^2+4x+3\)

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

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

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

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

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

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

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

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

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

7) \(x^2-4x-5\)

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

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

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

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

a) x²(2x³-4x+3)
= 2x⁵-4x³+3x²
 

yêu câu nhân hay phân tích đa thức thành nhân tử ạ

a: \(=x^3-2x^5\)

b: \(=5x^2-x^3+5-x\)

e: \(=\left(x-y\right)^3=x^3-3x^2y+3xy^2-y^3\)

 thực hiện phép nhân các đa thức