(c-5)^2 - 4c(-10-2c) = c^2 - 10c + 25 - 4c(-10) - 4c(-2c)= c^2 -10c + 25 + 40c + 8c^2= 9c^2 + 30c + 25.
(c-5)^2 - 4c(-10-2c) = c^2 - 10c + 25 - 4c(-10) - 4c(-2c)
= c^2 -10c + 25 + 40c + 8c^2
= 9c^2 + 30c + 25.