Question

calculati media geometrica a numerelor a=4+radical 80 si b=4(radical 5 - 1)

Answer 1

a=4+√80=4+√(16*5)=4+4√5=4√5+4

b=4√5-4

ab=(4√5+4)(4√5-4)=4²*5-4²=4²*4

mg (a.b) =√(ab)=√(4²*4)=4√4=4*2=8
as simple as that!!

Answer 2

a = 4 + √80  = > √80 + 4
b = 4(√5 - 1) = 4√5 - 4 = √80 - 4 

m.g. = √(a × b) = > √[(√80 + 4)(√80 - 4)] = √[(√80)² -4²] = √(80 - 16) = √64 = 8