Помогите решить!!! (c-2)(c+3)(c-1)²

= (c^2 + c - 6)(c^2 - 2c + 1)  = = c^2 (c^2 - 2c + 1) + c(c^2 - 2c + 1) - 6(c^2 - 2c + 1) =  = c^4 - 2c^3 + c^2 + c^3 - 2c^2 + c - 6c^2 + 12c - 6 =   = c^4 - c^3 - 7c^2 + 13c - 6