Question

Phân tích đa thức thành nhân tử:

\(a,x^2-2x-15\)

b, \(5x^2y^3-25x^3y^4+10x^3y^3\)

\(c,12x^2y-18xy^2-30y^2\)

Answer 1

a) \(x^2-2x-15\)

\(\Leftrightarrow x^2-2x+1-16\)

\(\Leftrightarrow\left(x-1\right)^2-4^2\)

\(\Leftrightarrow\left(x-5\right)\left(x-3\right)\)

Answer 2

\(a,x^2-2x-15=\left(x^2-2x+1\right)-16.\)

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

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

Answer 3

b)\(5x^2y^3-25x^3y^4+10x^3y^3\) 

 \(=5x^2y^3\left(1-5xy+2x\right)\) 

c)\(12x^2y-18xy^2-30y^2\) 

 \(=6y\left(2x^2-3xy-5y\right)\)