Question

x+y=21 si x(la puterea 2)-y(la puterea 2)=147 (((determinati nr reale pozitive x si y)))

Answer 1

x+y=21       x=21-y
x^2-y^2=147
(21-y)^2-y^2=147
441-42y+y^2-y^2=147
-42y=147-441
y=294/42
y=7
x=21-y=21-7=14
x=14
proba=14^2-7^2=196-49=147