x^2-280x+7720=0，答案是什么？ 拜托了，谢谢！！

Question

如题所述

Answer 1

x^2-280x+7720=0
x^2-280x = -7720
x^2-280x+19600 = -7720+19600
(x-140)^2 = 11880
x-140 = ±6√330
x=140±6√330