Квадратное уравнение имеет вид $$ax^2 + bx + c = 0$$, где a, b, c – коэффициенты.
a) $$3x^2 - 8x + 4 = 0$$, a = 3, b = -8, c = 4.
б) $$-5x^2 - 9.4x = 0$$, a = -5, b = -9.4, c = 0.
в) $$13x^2 - \frac{1}{3}x - 5 = 0$$, a = 13, b = $$\frac{-1}{3}$$, c = -5.
г) $$-1.3x^2 - 8 = 0$$, a = -1.3, b = 0, c = -8.
д) $$2x - 13x^2 + 9 = 0$$, a = -13, b = 2, c = 9.
e) $$x^2 - x + 5 = 0$$, a = 1, b = -1, c = 5.
Ответ: a = 3, b = -8, c = 4; a = -5, b = -9.4, c = 0; a = 13, b = $$\frac{-1}{3}$$, c = -5; a = -1.3, b = 0, c = -8; a = -13, b = 2, c = 9; a = 1, b = -1, c = 5.