Verified answer

[tex]x {}^{2} - y = 0 \\ x {}^{2} = y \\ y + 4 = 4x \\ x {}^{2} - 4x + 4 = 0 \\ x = 2 \\ y = x {}^{2} \\ y = 4 \\ x + y = 2 + 4 = 6[/tex]

Ответ: А