Question

lập đenta

x^2+x-2=0

Answer 1

\(\Delta=1^2-4.1.\left(-2\right)=1+8=9\)

\(x_1=\dfrac{-1+\sqrt{\Delta}}{2.1}=\dfrac{-1+\sqrt{9}}{2}=\dfrac{-1+3}{2}=\dfrac{2}{2}=1\)

\(x_1=\dfrac{-1-\sqrt{\Delta}}{2.1}=\dfrac{-1-\sqrt{9}}{2}=\dfrac{-1-3}{2}=\dfrac{-4}{2}=-2\)

Answer 2

x^2 + x - 2

= x^2 - x + 2x - 2

= x(x - 1) + 2(x - 1)

= (x + 2)(x - 1)