感谢楼主! 394 V1:(byyxz2289) DS:有两个点在直角坐标系里,(a,b)、(c,d),并且在y=X^2上。问y-intersect什么的。(这题我没看懂,蒙的,但是下面的两个条件是对的) (1)d=9 (2)ac=-3 参考答案A 1. a=3 or -3 , not enough 2. (1,1)&(-3,9) or (-1,1)&(3,9) two lines have the same y-intersect, enough 楼主忘了改答案了,解释是对的,答案是B -- by 会员 coloryao (2011/10/5 15:14:24)
Is this the same as this one? V3变体:(by frisun)【原 541 】
DS:两个点(a,b)和(c,d)在抛物线y=x^2上,且ac<0.问穿过这两个点的直线和y轴截距为多少? (1)ac=-3 (2)忘了…好像是个不等式 参考答案:E so THE answer should be A as well, right? |