楼上算错了
x^2 - 16x - 48 = 0
由求根公式：x = (-b ± √(b^2 - 4ac))/2a = (16 ± √(16^2 - 4×1×(-48))) / 2
= 8 ± √448/2
= 8 ± 4√7= =还没学根号要么是你老师题目出错了