Вправи 888 - 1000 » 995 (г)

г) 3x2 – 4|x| – 20 = 0; 1) x < 0. 3x2 + 4x – 20 = 0; D = 42 – 4 • 3 • (–20) = 16 + 240 = 256 = 162; x1 = (-4-16)/6 = (-20)/6 = –10/3 = –31/3; x2 = (-4+16)/6 = 12/6 = 2 – не задовольняє умову; 2) x ≥ 0; 3x2 – 4x – 20 = 0; D = (–4)2 – 4 • 3 • (–20) = 16 + 240 = 256 = 162; x1 = (4-16)/6 = (-12)/6 = –2 – не задовольняє умову; x2 = (4+16)/6 = 20/6 = 10/3 = 31/3; Відповідь: –31/3; 31/3.