Respuesta :

Answer:

100

Step-by-step explanation:

perfect square  (a - b)^2 = a^2 - 2ab + b^2

In this case

20x = 2 * x * 10

and

10^2 = 100

so

(x - 10)^2 = x^2 - 20x + 100

Therefore, the missing constant term is 100

.