Question

fie a,b,c,d numere irationale. demonstrati ca a+b*√2 = c+d*√2 daca si numai daca a = c si b = d

Answer 1

a=c⇒a-c=0
b=d⇒d-b=0
a+b√2=c+d√2
a-c=d√2-b√2
a-c=√2(d-b)
0=√2*0
0=0 (A)