Question

Suma a doua nr este 25,iar suma inverselor lor este 1/6.Aflati nr.

Answer 1

a+b=25 =>a=25-b
1/a + 1/b = 1/6
Numitor comun 6ab
6b+6a=ab
6(a+b)=ab
6×25=ab
ab=150
b(25-b)=150
b^2 - 25b + 150 = 0
delta = 625-600 = 25 =>rad.delta = 5
b1=(25-5)/2=10 =>a=15
b2=(25+5)/2=15 =>a=10