Question

x立方+3x平方-4x-12 x平方+2x-6y-9y平方 分解因式

Answer 1

x^3+3x^2-4x-12

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

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

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

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

x^2+2x-6y-9y^2

=(x^2+2x+1)-(9y^2+6y+1)

=(x+1)^2-(3y+1)^2

=[(x+1)+(3y+1)]*[(x+1)-(3y+1)]

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