Question

用直接开平方法解方程1.4x^2-1=0

Answer 1

（ 1） 4x^2 - 1 = 0

4x^2 =1

x^2 = 1/4

所以,x1 = -1/2 x2 = 1/2

(2) (x-3)^2 = 2

x-3 = ±√2

所以,x1 = 3-√2,x2 = 3+√2

(3) (x-1)^2 = 5

x - 1 = ±√5

所以,x1 = 1-√5 x2 = 1+√5

(4) 81(x-2)^2 = 16

(x-2)^2 = 16/81

x-2 = ±4/9

所以,x1 = 2 - 4/9 x2 = 2 + 4/9