Question

Punctul c)
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Answer 1

Fie    e  elementul   neutru.

xoe=x

xoe=(x-√2)(e-√2)+√2=x

x*e-√2e-√2x+2+√2=x

x*e-√2e=x+√2x-2-√2

e(x-√2)=(x+√2x)-(2+√2)

e(x-√2)=x(1+√2)-√2(√2+1)

e(x-√2)=(1+√2)(x-√2) Imparti    egalitatea  prin x-√2   si    obtii

e=1+√2