在实数范围内分解因式:(1)3x^2+2x-2;(2)(-1/2)x^2+2xy-(5/4)y^2
问题描述：
在实数范围内分解因式:(1)3x^2+2x-2;(2)(-1/2)x^2+2xy-(5/4)y^2
答
(1)3x^2+2x-2 =3(x^2+2x/3)-2 =3(x+1/3)^2-7/3 =3(x+(1+√7)/3)(x+(1-√7)/3) (2)(-1/2)x^2+2xy-(5/4)y^2 =-(2x^2-8xy+5y^2)/4 =-(x^2-4xy+4y^2)/2+3y^2/4 =[6y^2/4-(x-2y)^2]/2 =(√6y/2-x+2y)(√6y/2+x-2y)/2