①3(x-3）²-1/27=0
3(x-3)²=1/27
(x-3)²=1/81
x-3=1/9或x-3=-1/9
x=3又1/9或x=2又8/9
②9（x²+1)=10
x²+1=10/9
x²=1/9
x=1/3或x=-1/3
③25(x+2)²-36=0
25(x+2)²=36
(x+2)²=36/25
x+2=6/5或x+2=-6/5
x=-4/5或x=-3又1/5
④（x-1)²=25
x-1=5或x-1=-5
x=6或x=-4