题目

用直接开平方法解方程1.4x^2-1=0
2.(x-3)^2=2
3.(x-1)^2=5
4.81(x-2)^2=16

提问时间：2020-12-17

答案

（ 1） 4x^2 - 1 = 04x^2 =1x^2 = 1/4所以,x1 = -1/2 x2 = 1/2(2) (x-3)^2 = 2x-3 = ±√2所以,x1 = 3-√2,x2 = 3+√2(3) (x-1)^2 = 5x - 1 = ±√5所以,x1 = 1-√5 x2 = 1+√5(4) 81(x-2)^2 = 16(x-2)^2 = 16/81x-2...