Add math chapter 2, quadratic equation的题目

lin96

1）if one of the roots of the equation 2x^2+px-9=0 is twice the other root, find the possible values of p.

2) Given that alfa and beta are the roots of the equation 2x^2+3x-9=0, form quadratic equations with roots

(a) 3 alfa and 3 beta

感激不尽！

puangenlun

Given that alfa and beta are the roots of the equation 2x^2+3x-9=0, form quadratic equations with roots 3 alfa and 3 beta

a+b=-3/2
a*b=-9/2

(x-3a)(x-3b)=0
x^2-3(a+b)x+9a*b=0
x^2-3(-3/2)x+9(-9/2)=0
.......=0