Вправи 601 - 700 » 652 (3)

5(x + 2)2 + (2x – 1)2 – 9(x + 3)(x – 3) = 22; 5(x2 + 4x + 4) + 4x2 – 4x + 1 – 9(x2 – 9) = 22; 5x2 + 20x + 20 + 4x2 – 4x + 1 – 9x2 + 81 = 22; 5x2 + 20x + 4x2 – 4x – 9x2 = 22 – 20 – 1 – 81; 16x = –80; x = –5. Відповідь: –5.