(a + 2*b)*(a - b - c) - (a - b)*(a - c + 2*b) + 2*b*(b + c)
$$2 b \left(b + c\right) - \left(a - b\right) \left(a + 2 b - c\right) + \left(a + 2 b\right) \left(a - b - c\right)$$
(a + 2.0*b)*(a - b - c) - (a - b)*(a - c + 2.0*b) + 2.0*b*(b + c)
Рациональный знаменатель
[src](a + 2*b)*(a - b - c) - (a - b)*(a - c + 2*b) + 2*b*(b + c)
$$2 b \left(b + c\right) - \left(a - b\right) \left(a + 2 b - c\right) + \left(a + 2 b\right) \left(a - b - c\right)$$
Объединение рациональных выражений
[src](a + 2*b)*(a - b - c) - (a - b)*(a - c + 2*b) + 2*b*(b + c)
$$2 b \left(b + c\right) - \left(a - b\right) \left(a + 2 b - c\right) + \left(a + 2 b\right) \left(a - b - c\right)$$
$$b \left(2 b - c\right)$$
(a + 2*b)*(a - b - c) - (a - b)*(a - c + 2*b) + 2*b*(b + c)
$$2 b \left(b + c\right) - \left(a - b\right) \left(a + 2 b - c\right) + \left(a + 2 b\right) \left(a - b - c\right)$$
b*(2*b + 2*c) + (a + 2*b)*(a - b - c) - (a - b)*(a - c + 2*b)
$$b \left(2 b + 2 c\right) - \left(a - b\right) \left(a + 2 b - c\right) + \left(a + 2 b\right) \left(a - b - c\right)$$
$$b \left(2 b - c\right)$$