(x - 1)2 = 25
=> x - 1 = 5 => x = 6
hoặc x - 1 = -5 => x = -4
Vậy x = 6, x = -4
=>(x-1)2=52=(-5)2
TH1:x-1=5
=>x=5+1
=>x=6
TH2:x-1=-5
=>x=-5+1
=>x=-4
Vậy x thuộc {6;-4}
=> x-1 =5
=>x=5+1
=>x=6
KL: vậy x=6
=>(x-1)2=52
=>x-1=5
=>x=6
..................................................................................................................................................................
(x-1)^2=25
(x-1)^2=5^2
suy ra:x-1=5
x =5+1
x =6