1/2x в квадрате -1/2=1/6x(x плюс 5). решите уравнение

1/2 * x^2 - 1/2 = 1/6*x * (x+5)
x^2 - 1 = 1/3 * x^2 + 5/3*x
2/3*x^2 - 5/3*x - 1 = 0
2*x^2 - 5*x - 3 = 0
D = 25  + 4*3*2 = 49
x1 = (5+7)/4 = 3
x2 = (5-7)/4 = -0.5