Question

Se considera numere naturale x si y a)daca x+y=5 si x-y=3, calclati x²-y² b) daca x+y=6 si x²-y²=30, calculati x-y c)daca x-y=11 si x²-y²=44, calculati x+y

Answer 1

a).  x+y=5 si x-y=3 => x²-y²=(x+y)(x-y)=5*3=15 ;

b)  x+y=6 => x²-y²=(x+y)(x-y)=30 adica x-y=30:6=5 ;

c)  x-y=11 => x²-y² - (x+y)(x-y)=(x+y)*11=44  => x+y = 44:11=4 ;