could you help giving me explanations on this problem ? Thank you.

Let X be an unknown random 1variable. We ran n experiments for X, we denote he 1'; [i 2 ii) the number of samples that are equal to i. (a). Suppose that X is a binomial random variable {3(4, p} with p unknown. Show that the maximum likelihood estimate ii\" is equal to l. _ 11+2n+31r3+4 p _ 4H. * (Give a rigorous proof.)