Question

一道一元二次方程的题已知：X²+pX+q=0,当p²-4q≥0时,X=-p±根号p²-4q

Answer 1

（1）X1+X2=-p X1X2=q

（2）X1²-2X1+X2=(X1²-3X1)+(X1+X2)=2009+3=2012