ma=(a+b)/2=4 => a+b=2·4=8
mh=(2ab)/(a+b)=3,75
=>2ab=3,75(a+b)=3,75·8=30
=>a·b=30:2=15 =>a=15:b
a+b=8
15:b+b=8
15/b + b^2/b=8
15+b^2=8b
=> b^2 -8b +15=0
b^2 - 5b -3b + 15=0
b(b-5)-3(b-5)=0
=> (b-5)(b-3)=0 <=>
<=> b-5=0 sau b-3=0 <=>
<=> b=5 sau b=3
b=3 => a=8-3=5
b=5 => a=8-5=3
R: (a, b)€{(3, 5); (5, 3)}
