Răspuns :
x+y=5
x-y=3
x^2-y^2=? x=4 y=1 deoarece x=y+3 y^2+3=5y 2y=2 y=2:2 y=1=>x=4 y+x=1+4=5
x-y=3
x^2-y^2=? x=4 y=1 deoarece x=y+3 y^2+3=5y 2y=2 y=2:2 y=1=>x=4 y+x=1+4=5
x=y+3.
y+y+3=5/-3.
2y=2. y=1 si x=4
1 la patrat =1.
4 la patrat=16