x2-4x-5
=x2+x-5x-5
=(x2+x)-(5x+5)
=x(x+1)-5(x+1)
=(x+1)(x-5)
x2-4x-5
= x2-5x+x-5
= (x2+x)-(5x+5)
= x(x+1)-5(x+1)
= (x+1)(x-5)
xog oy đó bạn
5ting nha!
\(x^2-4x-5\)
\(=x^2-\left(5x-x\right)-5\)
\(=x^2-5x+x-5\)
\(=\left(x^2-5x\right)+\left(x-5\right)\)
\(=x\left(x-5\right)+\left(x-5\right)\)
\(=\left(x-5\right)\left(x+1\right)\)
Phân tích đa thức thành nhân tử:
x2 - 4x - 5
\(=x^2-5x-x-5\)
\(=\left(x^2-x\right)+\left(5x-5\right)\)
\(=x\left(x-1\right)+5\left(x-1\right)\)
\(=\left(x+5\right)\left(x-1\right)\)