Question

Dacă ×+y=5 si ײ-y²=15, calculati x²+y².​

Answer 1

Răspuns:

ײ-y² = ( x + y) * (x - y)

15 = 5 * (x - y) => x - y = 3 => x = 3 + y

x + y = 5 => 3+y+y = 5

2*y = 2 => y = 1

x = 3 + 1 = 4

ײ+y² = 16 + 1 = 17