Вправи 888 - 1000 » 995 (б)

б) |2x2 – x – 3| = 3; 2x2 – x – 3 = 3 або 2x2 – x – 3 = –3; 1) 2x2 – x – 3 = 3; 2x2 – x – 3 – 3 = 0; 2x2 – x – 6 = 0; D = (–1)2 – 4 • 2 • (–6) = 1 + 48 = 49 = 72. x1 = (1-7)/4 = (-6)/4 = –3/2 = –1,5; x2 = (1+7)/4 = 8/4 = 2. 2) 2x2 – x – 3 = –3; 2x2 – x = 0; x(2x – 1) = 0; x = 0 або 2x – 1 = 0; 2x – 1; x = 0,5. Відповідь: –1,5; 0; 0,5; 2.