РОЗДІЛ 4. Квадратні рівняння » 819 (3)

3) (5х^2-4х-12)/(х^2-4) = ((4х+6)(х-2))/((х-2)(х+2)) = (5х+6)/(х+2); 5x² – 4x – 12 = 5(x + 6/5)(x – 2) = (5x + 6)(x – 2); D = (–4)2 – 4 • 5 • (–12) = 16 + 240 = 256; x1 = (4-√256)/(2•5) = (4-16)/(2•5) = (-12)/10 = –6/5; x2 = (4+√256)/(2•5) = (4+16)/10 = 20/10 = 2.