36x-1=0 4x=81 （x+5）=25 x+2x+1=4

x²+2x+1=4
(x+1)²=4
x+1=2或x+1=-2
解得x=1或x=-3
x²-x-3/4=0
x²-x+1/4=1
(x-1/2)²=1
x-1/2=1或x-1/2=-1
解得x=3/2或x=-1/2
4x²-x-9=0
4x²-x+1/16=9+1/16
(2x-1/4)²=145/16
2x-1/4=√145 /4或2x-1/4=-√145 /4
解得x=(√145+1)/8或x=(1-√145)/8
　　祝学习快乐

36x²－1=0
36x²=1
﹙6x﹚²=1
6x=±1
x=±1/6
4x²=81
﹙2x﹚²=9²
2x=±9
x=±9/2

(1)
4x^2=81
x^2=81/4
x = ±3√3/2
(2)
(x+5)^2=25
x+5=±5
x=10 or 0
(3)
x^2+2x+1=4
x^2+2x-3=0
(x+3)(x-1)=0
x=-3 or 1