Question

Решите систему уравнений:
{x^2+y=25,
{x^2-y=7.

Answer 1

1)

$y = 25 - {x}^{2}$

$- y = 7 - {x}^{2} \\ y = - 7 + {x}^{2}$

2)

$25 - {x}^{2} = - 7 + {x }^{2} \\ - {x}^{2} - {x}^{2} = - 7 - 25 \\ - 2 {x}^{2} = - 32 \\ {x}^{2} = 16 \\ x1 = 4 \\ x2 = - 4$