Question

Phân tích đa thức thành nhân tử bằng phương pháp nhóm hạng tử

a)    x² - 3xy + x - 3y

b)    x² - 6x - y² + 9

c)    7x³y - 14x²y + 7xy

d)   16x⁴y² + 2xy⁵

e)   5x³ - 45x

Answer 1

a) \(x^2-3xy+x-3y=x\left(x-3y\right)+\left(x-3y\right)=\left(x-3y\right)\left(x+1\right)\)

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

c) \(7x^3y-14x^2y+7xy=7xy\left(x^2-2x+1\right)=7xy\left(x-1\right)^2\)

Answer 2

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

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

\(7x^3y-14x^2y+7xy=\left(7x^3y-7x^2y\right)-\left(7x^2y-7xy\right)=7x^2y.\left(x-1\right)-7xy.\left(x-1\right)\)

\(=\left(x-1\right).\left(7x^2y-7xy\right)=7xy.\left(x-1\right).\left(x-1\right)=7xy.\left(x-1\right)^2\)

Answer 3

d) \(16x^4y^2+2xy^5=2xy^2\left(8x^3+y^3\right)=2xy^2\left[\left(2x\right)^3+y^3\right]\)

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

e) \(5x^3-45x=5x\left(x^2-9\right)=5x\left(x^2-3^2\right)=5x\left(x-3\right)\left(x+3\right)\)

Answer 4

bạn kudo là CTV mà đi copy bài bạn MMS là sao?

Answer 5

a : x^​2​-3xy+x-3y = (x²​+x)-(3xy+3y)=x(x+1)-3y(x+1)=(x-3y)(x+1)
e: 5³-45x=x(5x²-8)

Answer 6

\(a.x^2-3xy+x-3y\)

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

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

\(b.x^2-6x-y^2+9\)

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

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

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

Answer 7

cám ơn các bạn nhiều