Question

phân tích đt thành nhân tử

\(x^2-x-12\)

 

Answer 1

\(x^2-x-12=x^2-x+\frac{1}{4}-\frac{1}{4}-12=\left(x-\frac{1}{2}\right)^2-\frac{49}{4}=\left(x+3\right)\left(x-4\right)\)

Answer 2

\(x^2-x-12=x^2-4x+3x-12=x\left(x-4\right)+3\left(x-4\right)=\left(x-4\right)\left(x+3\right)\)

Answer 3

x^2-x-12

=x^2-x-16+4

=x^2-16-x+4

=(x-4)(x+4)-(x-4)

=(x-4)(x+3)