Question

(X-1) ao quadrado=1
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Answer 1

(x-1)²=1
(x-1).(x-1)=1
x²-2x+1=1
x²-2x+1-1=0
x²-2x=0

Δ=(-2)²-4.1.0
Δ=4

-(-2)+/-√4/2.1

x¹=2+2/2
x¹=4/2
x¹=2

x²=2-2/2
x²=0

Answer 2

(x-1).(x-1)
x²-2x+1=1 
x= -b+ou-√Δ÷2.a
Δ=b²-4.a.c
Δ=(-2)²-4.1.1
Δ=4-4
Δ=0
x1=-(-2)+(√0)÷2.1 ⇒ 2÷2 = 1
x2=-(-2)-(√0)+2.1 ⇒ -2÷2 = -1