[交流] 【求助】各位大侠，求助三道高一数学题

Originally posted by cronozhang at 2011-02-03 10:30:21:
（1）注意到f（x）只有一个零点，所以f（x）是一个完全平方
即f（x）＝（x+t)^2=x^2+2 t x +t^2 且 t<0
所以 2 t = a 且 t^2 = a^2 -3
得    (a/2)^2 =a^2-3
得     a = -2

(3) x^2+5/2x+1 =0 易得 x ...

3楼: Originally posted by jiangwu8888 at 2011-02-03 12:26:43
第一问的答案是根号3啊...