Question

Phân tích đa thức thành nhân tử:

a. x²+4x

b. 16x²-9

c.2x-2y+bx-by

d.x²+4x-5

e.x³+x+5x²+5

f.x²+2xy-9+y²

g. x²-3xy-10y²

Answer 1

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

b, \(16x^2-9=\left(4x-3\right)\left(4x+3\right)\)

c, \(2x-2y+bx-by=2\left(x-y\right)+b\left(x-y\right)\)

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

d, \(x^2+4x-5=x^2+5x-x-5\)

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

e, \(x^3+x+5x^2+5=x\left(x^2+1\right)+5\left(x^2+1\right)\)

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

f, \(x^2+2xy-9+y^2\)

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

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

g, \(x^2-3xy-10y^2=x^2+2xy-5xy-10y^2\)

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

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