Контрольні роботи. ВАРІАНТ 1 » Кр-6 (6.1)

6. Розв’яжіть рівняння. 1) x – 2 = (x^2- 2)/7; 7(x – 2) = x2 – 2; 7x – 14 = x2 – 2; x2 – 7x + 12 = 0; x1 • x2 = 12; x1 + x2 = 7; x1 = 3; x2 = 4. 2) √7x2 = 12x + 4√7; √7x2 – 12x – 4√7 = 0; D = (–12)2 – 4√7 • (–4√7) = 256; x1,2 = (12 ± √256)/(2√7) = (12 ±16)/(2√7); x1 = 28/(2√7) = 14/√7 = (14√7)/7 = 2√7; x2 = (-4)/(2√7) = –2/√7.