Найду корень уравнения: x-0,64x=2,808
x - 0.64*x = 2.808
x-0.64*x = 2.808
0.36*x = 2.808
x = 2.80800000000000 / (0.36)
x1 = 7.8
сумма
7.80000000000000
=
произведение