👤

Daca x+y=8 si x patrat +ypatrat =38 atunci x-y=?

Răspuns :

x²+y²=38
x+y=8, ridicam la patrat
(x+y)²=8²
x²+2xy+y²=64  dar x²+y²=38⇒38+2xy=64⇒2xy=26⇒ 2xy=26
(x-y)²=x²-2xy+y²=x²+y²-2xy=38-26
(x-y)²=12
x-y=√12
x-y=2√3